Read the best Engineering guides for Vanilla / Classic WoW on the fansite WowIsClassic. Guides like "Leveling Engineering 1-300" will help you to quickly level up your Engineering from lvl 1 to lvl 300. You will also find guides that list the best patterns / recipes for Engineering , their drop locations and a lot of tips for Engineering in Classic WoW.
Here is the Engineering leveling 1-300 guide. Best tips for leveling your profession quickly