For team fights, you require good positioning and your teammates to peal for you, though this is less of a problem for Vayne and Kalista. Laning is so different for every match up and with how good/ who your support is that it's hard to say what to do specifically without you giving a specific problem you need help with. I'll just throw some random things out there. If your opponent is coming in to cs, landing 3 shots with vayne to win the trade isn't that hard. Ashe's W poke is pretty good too. If you have no sustain, giving up a few cs that would require you to be overextended or out of position is fine.
Also why do you have trouble auto attacking a single target with Kalista? Just click on the same target?
I just lolking'd you, I don't understand what you're having problems with. Your post seems like someone who doesn't know much about the game would ask, not a 4 season veteran question. There are a lot of adc pro streams out there you can watch. While the champs you listed have a playstyle a bit different from lucian, graves, or trist, it just comes down to slightly different positioning.