It surprised me to find that, although a fairly popular carry, Tristana has only two guides on this forum, while champions like Jax and Teemo have more than five. Being my current favorite character, I am disappointed to find such lacking resources. Thus, I precede to write my first guide, "Tristana: Ganking Goddess".
~Hit and Run (Burst DPS/AP)
-Annoying champs to lane against
Masteries will not be included, but in general, they should follow the build.
Tristana is a fairly balanced and versatile character, as well as fun and easy to learn. Her early game is one of the best, and her ganking abilities make mid-game go smoothly and late game explosive (pun not intended). Tristana's main functions include harassing, ganking, pushing, and supplying high dps--in other words, a basic carry. The catch is that she depends on items to make her worthwhile, but this in turn gives flexibility.
[Passive] Increases Tristana's range as she levels.
This passive is what makes Tristana better than other ranged carries. See "W".
[Q] Increases Tristana's attack speed by X% for 7(?) seconds
Caps at 90% attack speed, which is like giving Tristana another hit every second. Although the % is low at early levels, in late game, it will allow Tristana to take on multiple champions, or destroy a tower in a few seconds.
[W] Leaps at target area, dealing aoe damage of max 250(+1 per AP) and 60% slow for 2.5 seconds. Cooldown resets when you get a champion kill/assist.
This skill is the core of Tristana's ganking abilities. Leap onto an enemy champion and fire away with everything you have. By the time they get to the edge of your great range, they will either be dead or have taken quite a beating. You can also use it to escape by using it with "R" (ultimate).
[E] Passive: When ready to cast, enemies explode when slain by Tristana's attacks, dealing max 110 in magical damage to surrounding enemies.
Active: Shoots a shot which lowers targets healing by 50% and does 25 damage per second for max 8 seconds.
Great early game and farming ability. Allows Tristana to indirectly harass enemies by killing nearby minions, and the active side is frosting on your harassment. Later, the passive side works nicely with "W" when taking on a 20+ wave of enemy minions, netting wonderful amounts of gold in seconds.
[R] Ultimate: Far ranged shot that deals max 500 (+2 per AP) and knocks target back max 1000 distance.
Mostly a defensive move, although it can be used to last hit an enemy. You can use it for ganking as well--knock them into your tower and slow them with "W" and you probably have yourself a kill. Defensively, it keeps unwanted enemies away so you can kill their buddies, protect your teammates, or run away.
Personally, I usually take teleport and heal when I go to Summoner's Rift, and heal w/exhaust when I play at Twisted Treeline. Flash (I don't have it yet) would be great in either case, as well as Ghost and Rally. I would not bother taking the mana heal (don't remember the name) unless you are using an AP Tristana.
Tristana's recommended and most used build. Very good damage, above average survivability, but very costly.
~Hit and Run (Burst DPS/AP)
Best ganking build. Low survivability if caught. Depends on a good mana supply.
Able to take good damage, and can dish out good dps as well. Works best at assisting.
DPS with a twist. Instead of going for pure damage, goes for attack speed, critical %, and % damage.
DPS Tristana is, in my opinion, the best ranged carry in the game. Tristana is not quite the glass cannon that Ashe is, but can drain the life of any opponent, tank or not. On the other hand, you really need to be constantly killing champions and the dragon to support the build. You will also need to get the golem buff to use your champion abilities often.
Runes: Crit chance and/or attack speed. Mana regen also helps, as you will not be getting any mana items.
Abilities: Get W first (it can easily get you an early kill), then level E, with a few W's here and there. Always level your ultimate when it comes up so that you can increase its knockback (and damage). When you start to hit towers, jungle, or gank, get a few levels of Q to boost your damage.
Vampiric Scepter--makes early game a lot easier by keeping you in your lane as long as possible (turn into Stark's or Bloodthirster later if possible)
Berserker's Greaves--you won't need to be running away often, so attack speed is a better choice.
The next three in any order:
Frozen Mallet--For survivability. The slow also works wonders, so getting it early is always nice.
Hit and Run (Burst DPS/AP)
Actually, I have not tried a H&R Tristana build. Personally, I never liked AP builds, but I have included it here for sake of completeness. The point is to be able to spam Tristana's skills to get the most out of them. This way, you can constantly gank and keep your damage to the max. If you complete the build, you should have around 300 AP, which means something like 550 aoe damage for W and 1100 for your ultimate. Runes only need to have -10% cooldowns before you reach the -40% cap (Q at 5 seconds of downtime, W spam at 7.2 seconds, E at 12 seconds, and R at 36 seconds). Mana Regen (not including runes) is something like 50 per 5. I also got in +~1000 health and some armor and magic resist, but there is no HP regen, so you might want to add that in somewhere.
Runes: Cooldown is the most important here. Mana regen/HP regen is also nice of course.
Abilties: Get R>W>Q>E
Doran's Ring (replace later)
Boots of Swiftness--I believe speed is more important for this build than the AP of sorcerer's boots, because you need speed to chase and run.
Then get the following (no particular order)-
Of course, Tanky Tristana is another option. Here, you're point support your team in ganks by slowing down the enemy champion(s) as much as possible so that your teammates can take them down. You are not truly a tank, but your survivability is much higher than most. Costly build with damage on the lower side, so it is tough to pull off.
Runes: Health and Crit chance are preferable, but anything works here.
Abilities: Similar to DPS
Vampiric Scepter (change to Stark's later; Bloodthirster if extra damage is needed)
Boots of Swiftness (for chasing)
Then in any order-
Force of Nature
Like DPS, AS Tristana is a good ranged carry. The difference is that AS Tristana costs less, but has a lower end game result as attack speed reaches the cap. It also levels fast, and can solo the dragon at early levels and the Baron later with Stark's.
Runes: Crit chance
Abilities: Same as DPS
Vampiric Scepter (obviously, I like lifesteal)
Recurve Bow-->Last Whisper (Last Whisper is why this build is deadly)
Build Frozen Mallet and Madred's Bloodrazors
Upgrade Vampiric Scepter into something better
Game should be done, but if not, get Chalice of Harmony or some other item you prefer
Best farmer/pusher ever. Not much of a ganker though.
Items: Lifesteal item, Berserker's Greaves, Tiamat, Tiamat, Tiamat, Frozen Mallet
Extremely deadly. Just watch your back.
Items: Lifesteal item, Berserker's Greaves, M's Bloodrazor, M's Bloodrazor, (game over)
Items: Stark's Fervor, Berserker's Greaves, Last Whisper, Infinity Edge, Frozen Mallet, Bloodrazor/Black Cleaver
Items: Bloodthirster, Berserker's Greaves, Frozen Mallet, Infinity Edge, Atma's Impaler, Soul Shroud
Items: Lifesteal item, Berserker's Greaves, Tiamat, M's Bloodrazor, Frozen Mallet, Tiamat
Items: Lifesteal item, Berserker's Greaves, Last Whisper, Tiamat, Tiamat/Frozen Mallet/Phantom Dancer, etc.
Early game, try to solo if possible and don't waste time harassing. Tristana is a nice harasser, but I find that if I constantly try to figure out ways to kill the enemy laner, I will die instead. Just kill minions. Respond only if they make a move. Your aoe damage from last hitting should keep on the edge. If they come too close to you or your tower, then hit them with your slow and the DOT (W and E, respectively). This way, you won't have to worry about draining your mana, and your health should be fine because of the V scepter (that is, unless you are playing AP Tristana; if that is the case, lane with somebody else). After you get the money, recall when you have a chance and get your boots. When you get to level 12, you should have the items to be able to jungle for the Golem buff, then do some ganking and take out the first row of towers. As goes for all champions, stay aware of the map at all times so that you know when to gank/run. Don't let the other team catch you alone. Around level 16-18, if you have Stark's Fervor, you can probably solo the Baron. Don't spend too much time jungling though, as your main source of money should be enemy champions. Unless the other player is weak, don't gank alone, just in case. Whenever you can, rush a tower and spam Q till it is dead. Your champion will soon be a terrifying sight to behold.
Annoying Champs to Lane against:
Ashe--Volley and slow will keep you constantly at low health. Switch lanes so that you can kick her butt later.
Gangplank--Ultimate will kill you in seconds.
Morgana--Do I need to explain?
Anybody else with a slow/stun
Tristana lanes well with pretty much anybody, but somebody with stun/slow is always nice
Thanks for reading this guide. Questions, comments, flames--all welcome. Good suggestions are nice too. I will be periodically editing in case I missed something.