For AD carries (ranged auto attackers like Trist and Ashe), not missing a single last hit is even more important. The faster you can get your Best Friend sword, the better. It costs 1650, so it takes a while to get to. But it will make your damage output jump.
The only problem with learning one champion exclusively is that when they're restructured it can be difficult to adjust and then you feel like your foundation is gone. >_>
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~Peaf~
"Later that day, I f***ed a panda." - PSO