Yordle's Snaptrap is a good ability you should use to place on suspicious places to make sure you wont get ambushed, but you can also use it to flee by placing it a infront of your champion when fleeing, because it takes 1-2 seconds before it's ready to donate, you can also use it at your enemies tower if they survive with little hp because some doesn't mind it and that can lead them to death, in fights you can place them on your enemy, when it's donated it will root your enemy and make you able to see them, and it will also deal DoT damage (Damage over Time).

Piltover Peacemaker is good in the beginning because it sounds when you hit an enemy with it, so shoot it into the brushes and make you sure there is no one there before entering, and it also deals a lot of damage and it has a long range.

90 Caliber Net is used to flee,slow and even deal damage (But not much and it's better to shoot an enemy normally...). If you're supposed to flee you can run to a thin wall and fire the 90 Caliber Net away from you and it will deal a recoil that pushes you away. You can also use it to make your team to catch up an enemy.

Ace in the Hole is great when you're going mid 1v1, use it when your enemey is trying to flee and you can't hit your enemy with any normal attack anymore. Don't use it in team fights because enemies will block the bullet.

Headshot is best when you're in a brush, because it stacks 2 times instead of 1 time if you're in a brush. And at the eight shot you deal 150% Normal damage and 250% on a minion.

Armor Penetration and Magic Penetration is like the best runes for Damage, it's much better than AD runes or AP runes, but you should still use AD/AP runes, but for this champion she only needs AD so listen to my Build =).

I usually start with a Long Sword, because it makes my Q-Spell to cause more, and my attacks ofc.

Because you've got no extra HP at level 1 you should stay away from the brushes, and then stay back (But you should still try to deal damage) and play careful if you're going for first blood.

And then buy Berserker Greavers for movement speed and AS.

And then a Vampiric Scepter to keep your Health up.

Long Sword leads to Youmuu's Ghostblade (What you should use before all fights, but don't use it too early because it only has a 4 seconds duration, but it increases every hit) and it increases attack speed by 50% and your movement speed by 20, and it will make you able to chase enemies or flee or nuke.

And then you should buy The Bloodthirser for extra damage and Life Steal.

And then you should buy Phage for HP and Slow, And then you should buy Giant's Belt for HP, and those items leads to Frozen Mallet and you know why I picked it.

And then The Black Cleaver for armor reduction on your enemy (+ Bonus damage and AS).

And then Infinity Edge for the greatest AD.