Well, first, lets get this out of the way... Damage is limited to the skills and the ability, since wand damage is minimal.
The first 3 skills that you want to max are "firebolt", "lure of fire", and "cloak of fire". These are not set in order; you decide. Cloak of fire is your main damage dealing skill. It is interuptable duting battle, so cast it before battle. Firebolt is your basic relyable skill that you can cast over and over again during battle. Lure of fire is what can be used to weaken your target by making them more suseptable to fire damage (open up your battles with this).
As for stats... Like I mentioned before, wands do minimal damage.
Do not put any points into strength! Some mages find dex to be usefull. If you agree, and want to cast interuptable spells with less interuptions, put some dex. Focus and vitality are to argue for. This is where you must come up with a decision.
Do you want to have a ton of energy (and use energy shield as a tactic for tanking), or have alot of health that you can rely on? With warden gear and regen items, energy is plenty and doesn't act as an issue when it comes to using vitality. However, the shield tactic i mentioned requires all the energy you can get.
If you decide to go with vitality, you can always use "energy well" to boost your total amount of energy for 3 minutes.
I hope this helped. If you have any more questions, feel free to ask