Typically speaking AD Carry is probably my worst, or least favorite roll but I am an avid fan of pro competitions and I play all roles quite a bit so I think I can help here from that basis. I am by no means an expert on high level AD Carry play but I think some information could help anyways.
1. There are a lot of ways to play the game and a lot of strategies to choose from when laning and especially in bot lane where there is even more team play than usual. (I am assuming since you talked about ad carries that you are in bot lane with a support, if not then this probably still helps I think.) Depending on your collective skill level and your combo of champs getting kills may be more important than not, or at least easier to do. For instance if you were laning as a Vayne+Taric or maybe an Ezreal+Zyra then you would be in an aggressive "kill lane." This usually means that you plan to push the other players and get kills because your combo of champs works really well to that goal. Leona is another support usually associated with this aggressive style. A farming combo may be a Graves+Soraka or a KogMaw+Nunu who are naturally better at detering aggressive plays against them and sustaining in lane.
Regardless of that you want to "win" your lane. There are scenarios where you can be down a kill or so but you outfarm the other AD Carry and end up doing better in the long run. No matter what you do try to keep your farm up, and don't sacrifice yourself for a kill. At least not on purpose if you can help it. Getting kills is a great benefit but if you can work on last hitting and good farming then you should be ok without the kills, as long as you're not getting killed repeatedly anyways.
2. 2v1 is really dependent on the champions you're going up against. Typically you don't want to rush into that unless you're fed, skilled, or they are unskilled and you know it. If you keep map awareness and call for teammates to back you up then sometimes it's ok to "bait" them in a fight by diving then using escapes to lure them into a trap from teammates. However until you're getting close to full build I would usually not want to take 2v1 without a certain AD Carry champ. Instead you could try to pressure them by poking or something but be careful and cautious. If they are both low health then it might be ok. Really it's just about knowing your skill and what you're capable of.
3. If you are your teams AD Carry then you should be getting all the kills. The one character that no one should ever complain about KS'ing is your teams AD Carry. They have the greatest impact late game and require lots of gold in order to be effective in their role. If anything your team should be giving you kills when they can. I heard a lot of people complaining about KS'ing before I was level 30 but if your team knows how the current meta works and what roles everyone is trying to accomplish then you should certainly have the most kills. That's not to say some other characters shouldn't get any. Karthus, Jax, Olaf, Riven, Hecarim and others who are not actual AD Carries can carry games to a win and are extreme snow-ball champs that can get out of control. But typically as an AD Carry you shouldn't get complaints whenever you get a kill.
4. This is very dependant on the game. As an AD Carry gold is extremely important for you. You should always be looking for a way to farm. As a person who spent most of Season 1 and 2 as a jungler I can say that at the current meta, where junglers are usually tanks or off-tanks then they don't need to keep using the jungle for farm after the first tower is down a lot of the time. See if it's ok with your jungler to take some extra camps after you've pushed a wave. Whenever I play jungle I almost never pick up golems after my first clear so I tell the closest lane that they can have them.
After the first tower is down you'll usually see a shift towards roaming or teamfighting. As an AD Carry you should try to always stay with a bodyguard of some kind. If there is going to be a team fight somewhere then then be a part of it. If the two teams are facing off in mid but nothing is happening and you notice a huge wave at one of your towers then see if your team will back off to take care of it. Do not leave your team to do it on your own. As soon as it becomes a 4v5 then the other team (if your team isn't fed in some way) will probably dive and take your team out. It is important to team fight as a team. There are some characters that don't necessarily follow this rule; Twisted Fate, Shen, people who likely have a Teleport Summoner. These people can turn up at the fight just as it begins, however it is still important to stay with the group. Just stay safe. If their team is split up and you can see it on the map then you can probably go grab some farm.
5. Taking towers is a strategy you need to figure out for your team. Now in most solo que games this won't matter too much, just take them when you can. However if you ever get to do a 5v5 premade or something then you need to figure out how you want to deal with objectives. Objectives are things like towers, inhibitors, Blue/Red buffs, Dragon, and Baron. How you control these will massively effect the game and your play style. Korean, and asian teams in particular, seem to go for very aggressive and early tower kills to give them map control. Basically if you take the bottom tower down early then that creates a huge danger zone for the other team to farm in, they have nothing to hide behind in bot lane now. This could give you better control over dragon and if you ward a lot it will give you better vision. Other teams who are interested in a strong late game, like CLG.EU who are famous for there incredibly good stalling and late game strategies will try to never even hit a tower unless they need to. I often see them push a wave up to the enemy tower and then go do something else, letting the minions damage the tower on their own. This way the laning phase lasts longer and they can farm more passively. Typically I would say that, for me, if I start to win a lane and am around level 8-9 then i'll start pushing the enemy tower down if I can. If the enemy team takes one of your towers first however then it is free game, at that point try and take their towers at will. After the first tower is down is when I consider the game to have moved into Mid-game where roaming is more prevelant.
Another thing to note is when the enemy team is forcing an objective somewhere. If you notice that 4 members of the enemy team are in top lane pushing your tower and you know you wont make it in time to help then push their bottom tower, at least you'll trade a tower for a tower. Don't forget that towers give gold to all of your allies and killing towers in order to get to the nexus is more important than kills in the long run. If the enemy team dives your teammate in another lane and you can take their tower while they are distracted (in this case only if you can't make it in time to save that teammate) then take the tower. It's worth more than the bit of gold they got from that kill.
One more piece of advice: Map Awareness. More than anything in the game map awareness will win you matches. Wards are a major part of this, but in general looking at your mini-map about once every 20 seconds will go a long way. When you suddenly notice that the enemy mid just went out of sight while going bot through the river bush then it could save you. Make sure to call mia's in your lane if an enemy leaves it for any reason. If they went B and you know it then say that too because they could show up in another lane to ruin someone's day. Try and check the mini map close to 4 times a minute if possible and you'll become a better player very quickly. Junglers and Mid players have to do this more so than some other lanes because of how open mid lane is and how map aware you have to be just to do well as a jungler, but it helps every player.
Hopefully some of this was helpful, sorry it was so much. Good Luck out there summoner, and happy hunting!