Teachers and Students - How many Drills should you use??

[300Drive]

Trying to improve and have too many things I want to get better, so, how many drills do you recomomend one to focus on during, say, a 2-3 month period on the road to improvement?

By big issues are (not in order per say),

1) too long of a swing (extensor)
2) Right shoulder pivot opening too soon (my miss is a pull)
3) Tempo is way to fast, especially in the backswing
4) Not getting to both arms straight (winging it a bit)

Thanks.