First things first: GET FUSION BOLT ASAP. It will give you some damage that most low-level mages lack, all with bolt magic, which is easily obtainable.
I recommend collecting as many spell pages as you can find, and specifically going after the Thunder skill for your first intermediate magic spell.
Meditation and Inspiration are beautiful skills that make every mage's life easier.

Get a wand you can use for general casting that you can wear the crap out of. A lightning wand is where I started.
If you've got the money (~150k), upgrade a fire wand with Chain Casting +4 and watch enemies melt with your instantly casted firebolts. I still have mine I made when I started to this day.
Get either a Hermit's Staff or a Celtic Druid Staff if you can find one for cheap, but they're usually fairly expensive.

I made a post about mage combo tricks in this thread, so check that out if you haven't yet.

If you have more specific questions, don't hesitate to ask!