When I ADC, I typically AA the enemy laners from a safe distance (Trist, Jinx, Kog'Maw, Caitlyn are good for this because of their long range) while the enemy minions get their health lowered by mine. Poke the enemy laners, and last-hit when you can. Play aggressively because a lot of support players have no idea how to counter it (Believe me, it's pretty effective) but just don't overdo it (diving, etc.).
When you're under 50% health, play it really safe and make sure you have River warded at all times, because bot lane is a lane that gets camped a lot due to the jungler not wanting you as an ADC to get fed.
Jinx is my personal favorite ADC because of her great attack speed, long range splash damage, peel, and a great skill-shot slow that does a considerable good amount of damage. Her passive (Get Excited!) is a great way to get a kill and get out, or get a kill and chase, hence why getting a Pentakill on Jinx isn't all that difficult under the right circumstances.
Tristana does have a peel, yes, but it's not the greatest one. It's her only form of CC, and it happens to be her ult, which isn't on a short cooldown in the slightest. She has a great escape, but really should only be used offensively due to its damage and long cooldown. Basically, use her W when you know you're going to get a kill. It's a great tool for getting double, triple, quadra, or pentakills as it's a long-range initiate/disengage reset.
Tristana is also a great turret pusher; max E, then Q, put E on a turret, and AA it with Q active. Her E passive has a great deal of splash damage which is a great farming utility. The E active is a good lane harass and should really be used to get a good deal of damage dealt on both the enemy carry and support.
ADC isn't an easy role, despite popular belief, and there's a lot of responsibility on your shoulders when playing the role. You have to stick to the back lines of your team, and when your team dives, you're expected to follow up, because a lot of times the entire team's goal is to make sure the ADC gets the most kills as possible and the least amount of deaths so they can hypercarry into late-game. If you don't follow up on these, chances are your team will say in the chat, "wtf" or something along those lines.
My general advice is to stay safe but aggressive at the same time.
Good luck!