Get your hair cut. I mean REALLY short. Try to fit 'ooh-rah' or 'motivating' in every sentence. Practice staying awake for long periods of time while sitting in one place. Try to get your classmates to go for a group pee after pounding water with you and taking long walks in the woods. Constantly adjust your gig line on your belt and khaki-trouser combination. Stick around after class/work for a few extra hours each day, then have your prof/boss call you back soon after you've left. Think of new witty replacements for what 'TBS' stands for. Go out for dinner with two dozen of your closest friends and talk about nothing but work. Criticize the gig lines on their belt and khaki-trouser combinations. Cruise the bars with 10-plus dudes who have the same haircut as you and wonder why chicks don't seem to want to talk. Prepare yourself to NOT call the first 2ndLt you see 'Sir'.
Master these things and you will do well...
How could you forget the most important aspect? Think of the most logical way of doing things, and throw it out the window. Sure, you could get from point A to point B by marching there directly, but why not take a detour to Points C, D and while we are at it, Z! Since they are going to be make sure you get comfortable being uncomfortable, make sure you are training in the freezing snow, or the blistering sun. Or better yet, if going to a summer class, head to your local gym with some sandbags, and self-haze yourself in the sauna. Make sure you do Burpies (if you don't know what these are, you're in for a treat) until you become mildly heat exhausted, and then go on a 4 mile boot and ute run. Don't forget to go to a park or other wooded area with a million little bugs and get use to them buzzing in your ear and walking across your forehead. Sleep is overrated and start conditioning yourself to get only 4 hours a night, since you'll come to thank the dreaded 5 paragraph order for this. And always ensure your cammie paint is fresly applied, after all, its continuous!
Best of luck!

(For more information, be sure to check out "Alone and Unafraid" on YouTube)