Magicians stand at range and drop spells on their foes. As a magician, you have exceptional utility and deal good damage at range, but you tend to have little recourse when a foe gets into melee combat with you. As a magician, you should consider:
Arcane Bolt. This is it for a magician. You make your basic ranged attack with this ability, and you also link your spells to this ability. Most magicians are going to arcane bolt rated as high as possible; I’d recommend no lower than one rating below this. For example, as a magician built on 40 CPs, you can invest up to 20 CPs in arcane bolt (+8 rating). This is not a bad idea, and +7 (16 CPs) is a fair compromise to free up points elsewhere. If you start to drop to +6 (12 CPs) or lower, you are going to see your spells hit less often; and since many of your spells are usable only once per scene, you want to do all you can to make sure they’ll work when you use them.
Arms is where you’ll skimp. Your spell is the way you attack, so you won’t bother investing in precision or might later on, which means that having a big sword or crossbow is not going to serve any real purpose for you. Although you’d like a big suit of armor to protect yourself (who wouldn’t?), it’s hard to justify the expenditure here.
Aspect requires at least a moderate investment. Enemy casters will likely see you as a threat, and your wand or staff rating (for base spell damage) links to aspect, so this is something you have to consider. Your aspect should not be rated higher than your arcane bolt; remember that bonuses from successful attacks carry over to damage, so putting the emphasis on the active rather than resultant ability (arcane bolt over aspect in this case) is going to generally be the better choice.
Evade is VITAL for you. The whole idea is that you don’t get hit; if foes are striking you regularly, especially with physical attacks, you are going to start losing wounds quickly. Your spells don’t do you or your fellowship any good if you’re face-planted. Evade is your best defensive ability.
Intuition is similarly important. Many of your spells allow you to dictate the pace of combat; you can control enemies, stop them in their tracks, or remove them from combat altogether. You’ll want to do this early, so that the rest of your team can react accordingly; if you can stun the ogre (or bind him in place) for a few rounds, the rest of the team can focus on his pet wolf first; if you can’t, they’re going to have to wait on the wolf and take out the ogre before he starts pummeling them.
Might and precision are not worth any investment at all. Points here are effectively wasted; yes, it would be nice to be able to fight your way out of a web or shrug off the effects of the poison, but as a magician, you shouldn’t be putting yourself into positions where those things can get you anyway!
Resolve may be important as well. Resolve allows you to re-cast a spell you’ve already used, cast a spontaneous spell from your spell book, or beef up a repertoire spell that you have as an application; all three of these uses are incredibly valuable, and are well worth the investment of a few points into resolve.