Leveling Engineering is one of the more interesting professions and can be a lot of fun, but also very expensive. If you’re power-leveling two professions together, mining goes very well with engineering. The quickest way to level engineering is to buy all the materials on the auction house. Otherwise, leveling engineering can get pretty complicated once you get deep into it.
Ackis Recipe List, scans your trade skills and provide information on how to obtain missing recipes, patterns, enchants, plans, and schematics.
Engineering Leveling Guide 525-600
Engineering Leveling Guide 1-525
If you need more detailed information check out my favorite guides here.