For beginner/low lvl, I'd just pick professions that you can make money at; Herbing, skinning, mining.
I went skinning/LW myself, but I made the mistake of trying to do LW early to make "gear". I'd end up making something, which usually just ended up getting replaced by something better 5 lvl's later or something better from a instance. All of which made my wallet do a Yo-yo, due to using mats and buying them, along with the typical maintaince and such. U can imagine how pissed I was, way back b4 TBC when I spent months farming mats and buying the patterns to make things like a full suit of Black Dragon scale set...
All of which was replaced as soon as I stepped into Outland :p All that time and money down the drain...
Looking back, what I shoulda done was take a gathering job, make a profit, get my charater's lvl maxed, then with all the money I saved, powerlvl the profession I wanted fast, THEN make the gear I want.
Anytime I start a new alt, I just pick gathering jobs...I'll deside what I "want" to do with them way later.