İn early games with annie you can easily charge up your stun with last hitting minions with q with that way you won't lose mana and stay in lane more , after 2 level you can harass the enemy with q and w. First , charge your stun then stun the enemy with q because the enemy champion can dodge w or your ulti the best choice is q for stun in 1v1 . after stunning enemy don't afraid of use your basic attack in early game annie can do very good damage with her basic attack , use that combo in 2 level you will take the enemy's half hp , q-w-2 basic attack then go back to farming that way you won't take damage from enemy champion unless he got a huge range. when you become 6 level you can easily take enemy down with annie's burst damage . after charge your stun use q to stun enemy then use ulti after q because ulti got a aoe per second damage that way you can use the aoe damage more and take the kill .

Always stay near to bottom bushes of mid . when enemy come from top bushes go into bottom bushes then wait in there until the enemy ganker come close not to in bush , just close . after enemy comes use your q and w then stun him, the other mid lane champ ussually comes from their jungle way to there, when he do that way go to other bush that goes to your jungle , wait here untill both of them comes for attack you , when they come to your ulti range use e skill(for charge up the second stun) then ulti to both of them then w(to stun) and use q to the enemy mid champ because gankers are ussually off tanks and they ussualy got more hp then mid. after you do that combo the enemy mid champ if not fed his hp will down to 10% or 15% use ignite to him then do 1 basic attack and go back to your tower with using that jungle bush if enemy ganker still chases you use your ready skills to him to damage him more then go back to tower. that way you can kill both of them or just kill the enemy mid and don't die

İn early game just use q to last hit creeps that way you won't lose any mana and always be ready for killing enemy champ.

Always stay behind teamfight and use ulti first in teamfights to deal more aoe per second damage and stun 2-3 people to win the teamfight easily. when you're losing the teamfight say team to go with you to bushes run bush to bush to win teamfight with annie's stuns . focus 1 man , kill him and go to other bush until you think you can beat them