Great advice Whistle!
The only gear I would worry about is the 40s Shadoweave set. Its pretty good for the level. Don't worry about power leveling tailoring for it, you should be able to find a tailor to make it for you pretty cheap.
When I was leveling my warlock (2nd character), I used this guide:
World of Warcraft Guides | Warlock Powerleveling
It sums up how I leveled nicely. Of course, it is 2+ years old, and is just a
little bit out of date, but it still covers the basics.