While there's plenty of advice for learning roles in general, this is what ADCs have specifically that other roles don't always have:
Unlike mid lane, your power spikes are much more complicated than level. They're based on the first level of your ult, then it's mostly your items. Unlike top lane, you can't simply farm to get to those power spikes early.
This is where trading and freezing comes in.
If you are a hyper carry like Vayne or Kog, your power spikes are spread out a lot and are still enough to get early kills, but it relies on farming extremely quickly and getting all your CS, and it relies on a good support.
If you are an aggressive ADC like Ashe or Cait, your power spikes are most pronounced on ults and Zeal or BF sword. Ashe ults are probably what get her kills, Cait ults are what get her kills if she gets both enemy laners low early on.
Understand that the support owns laning phase and early game skirmishes, they zone the enemy off from zoning you, and they CC champs to let you get your damage off because you don't have burst to do so if they don't stand still long enough. You can be like Ashe and harass easy and initiate trades but if Soraka doesn't heal you as their Leona locks you down, the Soraka has failed her job as support. Usually small trades are won by sustain supports so try to get extended trades with champs like Blitz or Leona as they tend to get to both sides getting low enough to kill, which is what these supports excel at taking advantage of.
Always freeze if you'll lose trades, always push if the Junglers can't get involved and their support is strong in bushes.
