Source:
http://www.reddit.com/r/leagueofleg...i_placed_in_silver_1_this_season_today_i_hit/
turn on auto attack range indicators, I SWEAR THIS HAS HELPED ME ABSOLUTELY NO END. It allows you to become familiar with ADC's auto ranges.
following on from that, use attack move (mine is the default press "a") to CS in lane, you can CS with range indicator to learn your max range, it also helps when harassing the enemy adc to know exactly how close you have to be to land an auto. If you get used to using attack move to CS then it will help you get used to using it harass and more importantly in team fights.
LEARN TO KITE. literally, when I was learning to do this, I used to move while attacking CS with attack move, it helps you get used to the motion of using attack move which helps you when kiting.
pick 4 ADCs and LEARN THEM. I picked Jinx, Sivir, Ezreal and Cait - I still suck on cait but I'm getting better. I can now pretty much play most ADCS but originally I solely played jinx!
know your support match ups, don't go balls deep aggressive in lane if you have a janna (a bit obvious) - but also know when they are balls deep aggressive to play defensively. If you're a vayne you aren't gonna wanna trade with any ADC really unless you get a jungle gank.
learn to read bot lane "body language" if they have been playing defensively for 5 minutes then leona suddenly gets in the brush and acts aggressive you should probably run. Same applies if they are massively aggressive then switch to defensive, especially if they are pushed and thresh decides to stand behind his ADC near his turret!
know which adcs you do good against in lane (i.e. cait will crush vayne etc.) then play your lane accordingly - get as many autos as you can in and try to trade as much as you can.
This one may be a bit outdated, but still has PLENTY of good tips.
The champion specific items are really outdated.
http://www.reddit.com/r/leagueofleg...i_wrote_a_guide_detailing_a_lot_of_important/
