and to my above poster, Cleaver is much better than a 2nd phantom, because the increase in crit is very unneeded. You'll almost always crit with just IE and PD

Also, with BC you'll hit the cap anyway, so the extra AS isnt needed, and LW is only effective against very heavily armored people. Cleaver will eliminate 100% of a squishies armor, whereas LW will only do 40%

I agree about the runes with you however :P

I voted +1 though I have my own build, because this is a 3v3 build, and mine is 5v5, and also cause it's better than most builds on here, and is new, so I'd like it to get recognized :P

Switch your 1st rapid fire with your 1st rocket jump, you need that escape earlier

also, get boots (at least the 1st ones) a bit earlier. If I can I usually save up 2k instead of 1650, and get a BF and boots1 at the same time

You mentioned You're really squishy, but if you get a Mallet, or even a Banshees, you'll see a dramatic increase in your survivability!

One more thing, is you should not get hextech, it isnt good on her, though it's rare you'll finish the build anyway, as games tend to end :/

Just offering advice, other than those small things, everything is good :D

Crit runes are actually the worst runes you purchase. So I don't recommend Crit Runes, I recommend running flat armor yellows and MR blues to better cope with early game trade-offs.

Rocket Jump is widely seen as having priority over Rapid Fire. Rapid Fire generally doesn't provide a lot of 'killability' for Tristana until you have more items. The shorter cooldown on Rocket Jump is also essential to your survival, especially considering you recommend running Exhaust and Ignite

Additionally, running Black Cleaver is significantly less effective than running an additional Phantom Dancer. Phantom Dancer is a lot better of an item for the following reason: Movement Speed and Crit which influences our Infinity Edge. It also provides attack speed so you really won't be missing the cap. Generally it is better to get 2 Phantom Dancers than 1 BC and 1 PD. If you are looking for Armor Penetration Last Whisper is a very effective item for very cheap.

anyway, i won't vote up or down on this guide, considering I have my own Tristana guide, and that would be unprofessional of me to vote only to advance my own guide. but best of luck, hope you consider these changes