I also started just a week ago but I've learned a lot that would have helped me out if I had known. So let's see...

Pick Astral or Umbral. Probably better with Umbral for your status spells right now. You should put points into Ice, Water, and Earth because they're supposed to compose Umbral.

Make sure to get a shield as soon as you can (look for a square wooden shield) because with Sceptres in one hand you can use a shield in the other. Although I still don't have one...

It's really important to upgrade your weapon because it determines a lot of spell strength, especially accuracy. With your main spells costing 22MP a shot you don't want to them to miss or be resisted. I'm not sure about this, but I've adjusted my attributes to put a lot into Piety because it is said to determine magical accuracy. It's more important to hit with a spell and do reliable damage than to do a lot of damage but miss often.

Bio is a nice DoT that also reduces the targets attack. It's good to use defensive magic like this when you can.

Cast Sacrifice as soon as you lose enough HP to heal on the initial shot. For me it's something like 130-180. Then you have regen for the rest of the fight in most cases to support you. Sacrifice CANNOT save you if you're low on HP because it also COSTS HP to cast. Learned that the hard way.

Conjuror has a lot of spells you can use crossclass, especially Stoneskin and Shock Spikes. Spikes deal extra damage to enemies when you're hit and can stun. Stoneskin only lasts for 1-2 hits but it's good to give you a little boost at the start of a tough fight.

I can't recommend using Slow. It has a great effect, but the cooldown makes it a one shot spell in a fight. If it works, great. But it probably won't.