League of Legends (LoL) Question: what attack combo should i use that is best for annie?

If it's a champ with low mobility (Lux, TF,...) start with R then W - Q.
If it's a champ with high mobility (Zed, Leblanc,...) start with Q with stun up to guarantee the cc, then ult and W.
use your ignite too if you took it as summoner spell + electrocute rune is good with annie