I play lots of AD carry and I really want to get better at my role. I don't mind switching to any of the AD carries that I have, but I would really like to play just one champion for a while so that I can be a better AD carry overall.

AD carry Champs I Own:
Ashe
Caitlyn
Corki
Draven
Ezreal
Graves
Miss Fortune
Sivir
Tristana
Urgot
Varus
Vayne

Which one of these champions would make my game-play with all of the others better?

I voted Ashe, because I didn't see that you already own all these champs (honestly, IMO you've wasted a bit of IP buying so many).

Every one of these champs has a different playstyle. You're better off picking your favorite 3 or so and going with them.

My first was Kog'Maw, but I'd say Tristana is the best starter. Great gap closer/escape, no skillshots, and great attack range endgame.

Urgot isn't an AD carry, he's an AD caster.

Thanks so much for all of the input!

Graves

So many ad carries man, I voted ashe but you should have at least 3 ad carries in case of enemy pick and bans. The others either require team coordination/support coordination, pacing skills with autoattacks(varus) or have lots of skill shots you need to use for them to be viable.

Ashe, Tristana and Caitlyn are very good starter ad champs and I suggest you use them to learn. I also listed them in my opinion of pick priority.

Edit: Just saw you have graves, he is a very safe pick you could consider as well when it comes to learning adc.

kog maw owns

Trist is good because she excels in what AD carries are supposed to excel in: Positioning, Escapes, and Attacking from too far away for the enemy team to do anything.

She also has sick kill potential early game.

GRAVES.

The additional resists, re-position, AS steriod, and burst damage make Graves a formidable adc, while being easy to learn. He plays really fluidly, and is pretty straighforward to pick up.