When you first come into the game, it really helps to have a character sort-of thought out that you can play with. This can be a digital representation of you, or whoever. Be creative. But keep the following factors in mind: self factor, player concentration, faction build, and role characteristics. It'll help create a better character.
The first thing to talk about is self factor, which is how your character's presence affects the immediate vicinity. Are you a creepy and powerful crime lord who makes everyone shrink away and obey him with his mere presence, or are you an outgoing person that just seems to lighten the mood wherever you go? That is your self factor shining through.
Another thing you need to know about is player concentration. This simply refers to the areas of a map which are hot zones for players. In the case of ATF 5, for example, the major hot zones are Crane Town and Fort Outlook, and they can be said to have a high player concentration.
Thirdly, you need to be aware of the faction build of not only the map, but also the region within the map you're playing on. Which faction controls what area? How many people are playing that faction? This affects faction build. As an example, Crane Town's faction build is very highly twisted toward the CDF.
Last but not least you need to take into account the types of characters your fellow players are currently being. They may be playing as a USCPF general, and their role characteristics would reflect this. That player can be reasoned to be playing as a soldier who's grown tired of war, who is charismatic, gruff, and experienced, probably has a few war stories and scars to talk about. Those are all characteristics of that player's role.
For example, if you're going to live in one of the major scrap towns, you can take on a few roles. You can be a guard, a merchant, an arms dealer, a prospector, a card cheat, a barkeep or anything similar. It's highly discouraged you roleplay as an assassin or bounty hunter, as such jobs are non-existent today, and will be even more so in a post-apocalyptic wasteland. However, a mysterious loner is fine.
If you know the game you're roleplaying in, you're probably already well aware of the player concentrations and faction build of the server. If you don't, pay attention to the chat and try to explore the map as a lone wanderer. Go to the teleports you see people using often if you're in the lobby.
If you've played for a while you'll likely know your character better, and how other people respond. You'll become aware of your self factor for that particular character, allowing you to play to his or her strengths or weaknesses.
If you're the type of player that easily makes friends, this will be easy. Take into account your character's self factor, decide what faction they'd hang out with if they were people, and take that course of action. Know your preferred faction build, and work towards it. Examine the chat, know where the player concentrations are, and once you've developed your character, location, and faction enough, play to the role characteristics. Be polite IC and OOC, or just OOC if your character's a real jerk IC, work with everyone to complete jobs, gather some friends and go shoot rodents of unusual size in the wasteland, whatever.
Proper Chatting Etiquette
Pay attention to this, as it makes or breaks good roleplayers. The below examples are guidelines, but you're expected to follow 'em. Doing anything different is likely to confuse players.
If your character is speaking, it's either plain in the chat bar...
I need water.
...Or it's bookended by quotation marks.
"I need water."
Keep this in mind. I have personally seen many players signify action with plain messages, and I tend to read that as if they're speaking that.
If your character is performing an action, it's bookended by asterisks...
*I reach for the coins and grab them*
...Or by hyphens.
-I watch you grab the money, then pick up the ammo.-
One thing I'll say about marking actions, be brief, but don't be too brief. I like to indicate that it's my character performing the action by stating it in first person, in the present tense. One thing that I don't like is the whole -I would...- thing. It makes me think "But why are you not doing it?".
-I grab an IV of O negative blood...-
-...unpack the needle...-
-...and stick it in my arm.-
The last thing is out-of-character chat, or chat which isn't part of the roleplay itself. This is bookended either by parentheses...
(What's your character's name?)
...Or by square brackets.
Generally some people will double up their brackets, others won't. Either way is acceptable, as are curly brackets. As long as it's clearly marked in a recognizable way, almost anything can mark OOC chat.
\\ Oh, nice. My character's name is James.
Acronyms & Terms
There are a few acronyms and terms you'll need to know, as they're used fairly often for RP. These are all considered OOC, and must be bracketed.
Firstly is PTK, or Permission to Kill. This rule is in place to prevent outright banditry. Once you give this to a certain player, they can kill off your character. RTK, or Reason to kill. Is the only way to bypass PTK. It is granted by admins only, and is only used when some other player ICly does something that would be reacted to with killing the char.
In a similar vein I personally ask PTHG, or Permission to Harm Grievously. In a similar vein, this is basically killing someone, hence why I ask permission. However, PTHG isn't a rule.
Next thing you'll encounter is Void, which players will say if they consider a previous action null or void. I personally find it helpful to quickly describe the action, but if you don't, void always voids the most recent action you took as a player.
If you disagree with an action another player took against you, you can ask them to void that action. Work it out OOC, void as required, and get on with the RP. Don't make a fuss about it, or people will be telling you to BTRP.
Next is BTRP or Back To Role-Play, which may be asked of you if you're overusing OOC chat too much. People don't like it when other people fill the chat with their latest exploits in -22º or Island of Mezaa, or anything else. If someone asks this of you, please be courteous and leave your tall tales quiet for now.
This isn't Second Life, keep your sexual misadventures out of ATF. It breaks Roblox ToS and detracts from the experience for others.
There are several things which people detest, and often they're simple mistakes. Please take note of this, as this can and will make or break your reputation.
Godmodding is one of those mistakes. A character can't outright kill someone, or can't dodge bullets, and definitely can't survive a fall from the top of the crane in Crane Town and walk away with not even a scratch.
However, if you didn't give PTK to the people actively killing you, and you've asked them to stop with no response or no OOC bartering, you -CAN- shrug off their attempts at killing you, even if that normally would be considered godmodding.
Another mistake is cutting in. This is where you jump into another person or group's roleplay in a faction considered unacceptable. For example, if you're in a wasteland or subway, and you see another group, be cautious. Figure out their role characteristics through observation of the chat, plan a time to enter IC, or ask them OOC beforehand.
Similarly, if one faction attacks another, the attacking faction should use OOC to make the defending faction aware of the attack, out-of-character. Now, if the defending faction immediately prepares an impenetrable defense without having received IC warning, that is godmodding. OOC and IC information are considered to be separate.
This is trickier than the above two, since it spans a very wide spectrum of possibilities. However, generally this applies: If you encounter a roleplayer that affects the story you're playing in in a way you consider unacceptable, let them know. If they don't do anything about it, it's your choice whether you continue or ignore them.
Rules to note
These rules are rewritten from BH502, self-proclaimed mini-moderator. Some of them are hinted at above, but they're cleared up here for convenience.
This covers a spectrum of mistakes, and can be considered general. It is either not RPing, or RPing poorly. As an example, one cannot hit another player when out of range of that player. They first have to move in range of the other player to interact with them.
As mentioned earlier, godmodding is basically not taking your hits, or having access to something that you wouldn't have access to. As an example, imagine this. A guy walks into Cranetown, completely kitted up with military Kevlar body armor and bandana, a stupid amount of money, and powerful guns, climbs up to the tower, survives being shot in the face because of his Kevlar bandana, and proceeds to then jump off of the crane and walk away as if nothing ever happened.
Failing to tag messages
Come on guys, this one is easy. If you're highlighting an action message, tag it with dashes or stars. Don't leave it bare, because that's talking IC. Don't you hate people who narrate everything they do? And OOC talking uses anyone of a number of different patterns of brackets around it. Please, just bracket OOC messages with curly braces, brackets, or parentheses, whether single or double. It'll make life easier for everyone if we just do this right.
Lore breaks and fail wardrobes
The world of ATF Rain is hot. The world of ATF Snowstorm is freezing. Neither game has place for doges, robots other than SEALs, any sort of package that has a texture, crazy wing hats, and other types of clothing. Oh, and if it's freezing out, don't wear a miniskirt and a sports bra. You'll freeze to death.
With regards to lore breaking, this may be hard to understand. For starters, read the game guides (available on each game's page), find out which area is held by which faction and whether it can be raided, and check the server you're on before you take over Cranetown for the Mafiya. In ATF Rain, Cranetown is loaded with CDF NPCs, so any attempt to take it over has to fail by default.
I mentioned this above. Erotic roleplay is just disgusting. Save it for imvu or second life or even just a private skype chat. Besides, most players aren't even eighteen yet. It's not cool, so don't do it. Erotic roleplay is another term for cyber sex, which is something you should avoid in the first place, unless you know the other person in real life. However, if you make out, keep it clean, and time skip past the steamy bits, your relation with a character in game isn't considered to be erotic, and the same goes for kissing, hugging, and cuddling.
Gaining advantages through OOC, like using third person to gain information about one's roleplay.
Guns are dangerous things. The universe of ATF isn't the universe of Borderlands. Guns have safeties on them. In the universe of ATF, machine gun fire is NOT a suitable substitute for proper role play. If you shoot once or twice accidentally by misclicking, and you void it immediately, it's fine. Keep doing it, however, and you're random shooting and can be kicked.
Spamming, trolling, or harassing someone in the chat isn't cool. It's also illegal depending on where you are.
Votekick system abuses
Please do talk to people before you kick them. Let them know what they're doing wrong. Let them fix it. If they don't, then kick them, and please do leave a note of why you did with the admins. A simple ":So and so was kicked for erotic roleplay" is enough in the chat, as that gets logged. Similarly, please kick for valid reasons only. Abusing the kick system to silence someone you can't get along with is a kickable offense and also not cool. So just don't do it. Just kick when it's necessary.