Good for you starting early. Do this, and you will almost certainly be wealthy by the time you are 30-40:
Start investing now, as much as you can with every paycheck. First max out your TSP (401k plan), then Roth IRA, then taxable accounts (a regular brokerage account with no tax advantages, like with Vanguard). Follow a healthy asset allocation, primarily in indexed stock funds. Avoid any kind of exotic financial instruments/schemes, whole life insurance, expensive or "loaded" mutual funds, individual stocks or day trading. Put all this investing on autopilot, so that it just comes out of each and every paycheck, and live on the rest.
Since you are currently getting a housing and food allowance, you should be able to invest a ton. If you can invest 50% or more of your total earnings each month, you will be wealthy in almost no time at all while you are still a very young man.
Optional: If you have or develop an interest in real estate, it is another great way to develop wealth, diversify your assets, and hedge against inflation and stock market downturns. Owning property(s) in a good market can lead to a lot of gains over time.