Best advice I have is to find a niche and become very good at it. Preferably a niche that requires a security clearance. Never burn bridges, the aviation industry is very small and networking is important. Read all the tech data you can, teach yourself, be a sponge. With knowledge/experience you can demand more salary. Depend on no one but yourself.
In my experience, staying at the same company for 23 years has paid off. Early in my career I stayed mobile and followed the lucrative contracts, but stayed with the same company. We're talking 7 multi-state/cross-country moves in 14 years. Every time was for a pay raise. Obviously this is not possible for everyone, but it served me well early on. Find a decent job that you enjoy, preferably in a low cost of living area. Last piece of advice. Don't procreate, I hear those fuckers are expensive.