Might I reccomend Mining/Tailoring for your mage?
Mining, unlike any other gathering profession, starts off profiable and only gets better. A stack of Smelted Copper (20 bars) sells between 50 silver and 1 gold (sometimes more!) on the AH, no regardless of faction.
Due to the high cost of Copper, and copper being the main ingredient in most Blacksmithing formulas, this makes Blacksmithing VERY expensive. (Even if you farm your own minerals, that's profit lost by using it, not selling it. I believe the Economic term is "Oppertunity cost.")
Why not have twice as much Mining power, and take Mining on both characters? Mine, Smelt, Sell. It's how I made 100 gold by level 25 on my very first character. Now I usually have 100 gold, and 6 12 slotted bags by level 20. (I've started over on a four different servers. Stupid friends moving around. *grumble*)
When you're soloing, get to every ore vein possible.