Military Links
Let's face it--if you've never been in the military, the idea of military RP can be daunting. But as with all things, a little bit of research can help inform your RP and make it more realistic. And the beauty of it being RP is...you don't really get hurt (or at the very least, actually have to do pushups) if you make a mistake! So here's a few links you may find interesting and/or helpful.
Military tactics: http://en.wikipedia.org/wiki/List_of_military_tactics
Fire Team formations: http://www.bu.edu/nrotc/semperfi/ftx/ftf.htm
Another link on formations: http://www.citadel.edu/root/images/Marines/Docs/ICS0904-Combat-Formations.ppt
Hand signals: http://www.uscrow.org/downloads/Tactical%20Hand%20Signals.pdf
Infantry squad tactics: http://www.military.com/forums/0,15240,79595,00.html
Tactical movement and Concealment: http://uscrow.org/2013/04/06/tactical-fire-team-movement-and-concealment-guide-for-combat-survival/
Strategy vs. tactics: http://www.molossia.org/milacademy/strategy.html