If you have a digital camera, take a pic of yourself. Try it out naked, you'll be the only one seeing the pics. Make sure you get a front and back.
Open the pics in photoshop and trace your outline and any relevant musculature you like. Fill it in with grey about 70% for the lighter skinned peoples (look in the color chooser people!).
Once you have that, create a new layer and basically draw whatever style of clothes you feel you need practice in. This way you don't necessarily need to worry about the proportions and angles of the body, you can concentrate on the stuff you need to work on. Make it rough, make it sketchy, give it a painterly feel, make it a great addition to your portfolio to score that elusive job. Just get better.
And that's it. Practice.
PRACTICE.
I felt I needed some practice with modern soldiers.
