Cactus del Jack
Annie go on the mid lane, to level up fast. She is playing def, till stun is ready and she is level 4 or 5. Then you can start your first attack vs. the enemy champion mid. First Exhaust, then stun with Disintegrate and then Incinerate. If you have luck you can kill him, if not, he will go base.
Now you Level up to 6. Go Base, and Teleport back. Make your Stun ready. Play def till Exhaust is ready. Kill enemy Champion with first Exhaust, then Tibbers and all the other skills.
In the midgame you have to gank.
So push till creeps can hit first tower and change lane to gank with your team. While changing lane you can make your stun ready by creeps in the wood or mana buff.
Now you should have Banshees Veils, Boots of Socery, Rod of Ages and Nashors Teeth. Now you can make a lot of damage in a short of time. So run with your together to search for a clash and destroy tower. Don´t forget the Dragon or Baron Nashor. You need money for Rylais Zepter and the Ring.
Important is, that you have the stun always ready. And Tibber is your best weapon to make an aoe stun.