The problem with Kogmaw is that I am not skilled at leading the opponent. As for Tristana, I haven't played her enough yet. She seems viable, though. I think my main problem is positioning, though. With Fiora, I enjoy shredding opponents with a few quick hits, then moving to the next. Plus, her ult allows me to survive a bit until my team comes while killing them. I want a ranged who can do that too, or at least rip people apart quickly. If positioning is my problem, then I need to find someone who can move around well, and still deal a lot of damage quickly.