just watch doublelift / aphromoo videos, granted they might seem trolly, they have good mechanics and positioning.
overall in the bot lane
stay parallel with your support (meaning be ready for when you want to harass/poke/engage together), last hit, harass the enemy laner when he goes to last hit a minion, dont push the wave (unless you are warded and wont be ganked). and make sure you go in when your jungler gets to lane (all too often adcs stay on minions while jungler and support are diving the enemy adc, and there you are, last hitting minions when you could be getting a kill).
thats pretty much everything an adc needs to do in order to have a successful lane. there are champion specifics like draven vs kog maw, put the hurt on vs passive farm till 6.