First thing is get a good understanding of your budget and spending needs- not wants. it is important to remember that you can't invest until you can save.

Secondly, take advantage of all the military financial benefits such as the using the TSP in the Blended Retirement System. Depending on your level of service you get up to a 5% match on your investment. That's free tax-free money. The new retirement system is like a private sector 401k so even if you don't do your 20 years you can take it with you. The other the VA mortgage. You can actually use it to buy a building to rent out 4 apartments - as long as you live in one unit for a year.

Third, invest outside of the TSP. The match is its best benefit but its investment choices are limited. So, use the VA mortgage to get you started in Real Estate. But the easiest and most proven investment for the long term is a portfolio of US stocks. Long term returns hover around 10% so it is your only shot a battling inflation.