How did you manage to do anything in engineering without mining? If you're completely new to the game, then I'd suggest going over to the world of warcraft forums, and reading up on different races, classes and professions.
http://forums-en.wow-europe.com/
Also, if you have a spare £10 or whatever it costs, then it may be worthwhile purchasing the official game guide and just having a read through. It's not really useful once you know what you're doing (and can just check thottbot.com instead
), but it does give quite a bit of unbiased information about each class and some of the areas I believe. It's a good place to start if you don't want to trawl through some of the flaming on the forums.
For a warrior, blacksmithing/mining is probably the best combination as it creates weapons as well as armor. Get first aid too, and cooking may be useful to you as you can't heal. Small tip for cooking - if you wait until you're at an inn, there will always be a fire you can cook over, so you don't need to buy flint and tinder or wood.