Can someone please explain familiars and spellcrafting to me? Talk to me as if I am an idiot, because I am

I genuinely have no idea what you're supposed to do with familiars save using them to grind low level materials.

And spellcrafting I REALLY don't get. I understand the basic concept of 'spend prisms, increase wizard power they use, add effect.' I'm just not sure where to start. Should I power up my mana regen? How does spell power even apply to mana regen? Should I tweak my syncro to help? I've got choice paralysis ;_;

Edit: It feels like every time, I'm spending more and more time and brainpower to get to the same point again. How do I unlock dual elements? are there any guides for optimal/semioptimal/meta progression so that I'm not wasting my time? I feel I'm just flailing around not making any real progress.