First
to the forums! Pull up a keyboard and stay a while.
Second
Lots to be learned from this place, some great information to be found
Third
See this topic for basic airbrush techniques http://www.finescale.com/fsm/community/forum/topic.asp?TOPIC_ID=34208
Fourth
Bookmark these two sites, they will save you time, money and effort:
Music City's http://www.craigcentral.com/models/ and Swanny's http://swannysmodels.com/ Scroll down and read all their tips and info. You will be happy you did. If these two gentlemen don't have the answer, I don't know who does!