I wanted to start putting perks into either illusion, conjuration, restoration, or alteration. Which would you guys say is most useful?

Also, is lock picking or speech worth putting perks into?

I am no pro or nothing, but I went with Restoration (lvl 10). I don't want to be bogged down by shields later on in the game. Early it has paid off. I regenerate 75% faster magic so I can typically blast fire or whatever else and dodge and restore my health if I am fighting another wizard.

Conjuration is just godly. Nothing beats summoning two Dremora Lords or two Atronachs.

Destruction or restoration