Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
This is the build I'm gonna use once i get level 30.
Most of the itens already tested now, once i test everything i'll get all the points for it.
Revive Spell: I usually use it on 2 times, when we're attacking, if i die, i get the revive with the high speed boost, getting back to the fight very fast. And when we're getting attacked, especially if theres a lot of super minions, tristana is the best farmer.
Heal Spell: Since the start till the end of the game its way too usefull. Especially when youre being attacked by 2 or more enemies, you can just heal yourself and run. People usually use Exhaust, but its only one target, depending the gank it may be not usefull.
On skills, i leave Rapid Fire for the end game, since your mana is too low on the lower levels, its more usefull use the mana on other attacks.
Attacking way for me is: Jump on back, Buster, Active Rapid and Throw Explosive.
On my mind, Dorains Blade is the best for the start, you get a little more HP, also some attack and life steal. Try to stay on line till you get 1.500+ money, so you can get the boots and Scepter (to start Malady), then make your way, Malady - Phantom - Infinity - Bloodthirster, and the last Frozen Malet (sell the dorains for the slot).
If you're in a very long game, its a good way to get another Phantom, selling your Boots.
I might edit this more. But for now this is a bit of the way i play with Tristana. Hope you like.
Wanna shoot something? ^^