Start at a good pace and try to maintain. the problem with a lot of runners is they will try to stay near the front and tire themselves out by expending to much energy at the start of the run. Also, keep your head up, or even tilted a little higher than normal to open the pathway for air (just a little though, don't run looking at the sky or nothing, it's obviously going to make it harder to run). Don't overdress, after a mile or two you are going to be sweating, that's not to say don't wear a jacket or even a light coat if it is cold outside, but try to dress in light garments, don't wear a huge puffy winter jacket with huge gloves, being a little cold when starting will even out to being a little too hot when you finish and all those clothes is just going to get in the way. HYDRATE, and i mean like a week before really start drinking a lot of water so you're body will retain it. Also eat salty foods (don't go crazy) to help retain water. Last, stretch. A lot the day before and also before you start running.
I was in the Army, so trust me I know all about running.