Hi i'm Mario and this is my Poppy's build. She is very good counter top for many ad champs like gp , tryn and others. She is one of the most op champions late game, In teamfights she can burst enemy ad carry and your team will win for sure.

Items are different against different champions. If your top lane oponent is making Magical damage you must start with Boots of speed and 3 pots , but if he is ad champ you could start again with boots of speed but i think if you start with Doran's shield it will be better. After the first back you should take boots of speed and Madred's razor ( for ad oponent) or rush sheen (for AP oponent or you think it will be better) . Then you must finish Wriggles and Trinity force. After Trinity Force you can build Guardian's angel, Black Cleaver or Maw of Malmortious ( you will deceide witch one will be first ) , In the late game( after you build 6 items) you can sell Wriggles and buy Bloodtristler.

Pros
Great turret diver
Stun
Incredible Ultimate
Unstoppable when fed
Extremely fast
Difficult to kill (passive)


Cons
Picked on by ranged
Terrible farmer
Vulnerable to cc
Not very powerful early game
No sustain
Mana Hungry

Top Choices
Flash - One of the best summoner spells in the game. With flash you can easy escape from gangshttp://www.mobafire.com/league-of-legends/edit-build?edit=203602#
Ignite - With ignite you can burst you enemy easylier
Exhaust - Best against Ad champs like ( tryn,lee sin, jax )
Ghost - Other good spell. With your W you will be really fast :)

Your passive gives you huge survivability throughout the game, but it is especially useful early game. This is the reason Poppy is sometimes used as a tank. Every single hit that does more than a tenth of your current health is reduced in half. This is really usefull. This means when you are at about a quarter health, all of the attacks you'll be taking from other champions is cut in half. This build uses Poppy's passive as a way to remain slightly less squishy and still be able to go all out with offensive items. Remember though, the passive doesn't work on turret shots!The passive can stop AP carries' burst in teamfights.

This skill will be your main damage. It's what makes Poppy one of the most frustrating carries to play against, and possibly the best carry in the game. With this build, your devastating blows will be hitting for over 1k damage. Trinity force works perfectly with this skill, making your damage huge. Also, the cooldown is around 3 seconds! This skill makes Poppy's DPS just plain ridiculous. Grab the blue buff as often as you can, and the cooldown will drop even further.Also it makes percent of health(magic damage).

This skill gives you an increase in attack damage and armor for as long as you keep attacking or being attacked. This can make a big impact early game, as you can deal a lot more damage without having to invest in attack damage items yet. The real benefit to this skill, however, is the speed boost it gives you. It's like a mini ghost that recharges very quickly. Use this skill to get in and out of battles. Early game it helps you farm a bit faster and get out of tough situations. It helps you to use your Heroic Charge successful. Armor bonus helps against ad champs.

This skill has many uses, and its what you'll start off with. It's great for closing distance between you and an enemy and will be your best friend throughout the entire game. While ganking in the beginning of a 3v3 you can easily hide in a bush, charge the enemy into a wall to stun them, and take them out quickly. Remember, when you tackle an opponent into a wall or turret, they take more than double damage what they normally do from this attack and are stunned for 1.5 seconds. This can make a big difference. Always try to set up the tackle into an object. Also you can use it on minions for closing distance or for running.

Poppy's ultimate is incredibly useful. You use it on one target, and you deal extra damage to the target without taking any damage from anything else in the entire game and you can't be stunned,snared,silenced, you can't be stopped. This includes turrets and other champions! This is how you will pull off some ridiculous tower dives. Be careful though; once the target is killed your shield goes away, leaving you very vulnerable. A great idea for a 5's team fight is to use immunity on a tank or mage that's out of mana and then kill their carries first while they can't harm you. Really useful for 1v1 fights or 1v2.