So, when you run your first race, you go out too fast. Everyone does. It's a universal truth of running races. In the excitement of the race, you lose a feel for what your body is actually capable of, and your competitive nature combines with a bit of herd instinct. You fly past others for a brilliant five minutes or so, before your body says no, and you stop, catch your breath, and slog your way to the finish line.
This tendency isn't unique to new runners -- it's just that experienced runners are aware of it, while new runners are unpleasantly surprised. All runners face the same issue: you never quite know what you are capable of when you stand on the starting line. We aren't equipped with accurate fuel gauges, and the blend of race excitement and well-meaning-but-misplaced-positive-thinking can result in overestimating what you actually have in the tank. It's a really bad idea to rely on how good you feel at the start.
[this is why I HATE going into races confident, and HATE it when people feel compelled to tell me I'm sure to PR, etc. It encourages it me down the path of bad early pacing decisions. My best races have all happened when I doubted my ability to even finish as I stood at the start.]
If you're smart, you recognize this, and figure out ways to address it. One of the easiest ways to do this is to pace off of others. The thought process goes like this:
"Hey... I remember that person -- he destroyed me last time. I probably shouldn't run my first mile ahead of him again."
Assessing your pace by others is a useful tool. And as you race more and more, there are more familiar faces to use as early benchmarks, and so you have multiple points of reference to help you keep the brakes on.
[Of course, using others to judge your pace can backfire in the case of inexperienced males in their 20s, who employ a variant that is best described as do whatever you can do to stay ahead of all females at all points of the race at all costs. These guys generally indulge in 2-3 spectacular surges, each followed by a rest break, before death marching the remains of the race.]
There is a hitch, though. Just as you never know exactly how much you have, you don't know how much those around you have either. Pacing yourself against others can limit you. Perhaps today is the day that you finally are faster than Suzy. At some point, you have to shift to trusting how you feel, and not letting the fact that "she's supposed to be ahead of me" limit you from your true potential that day. At the end of the race, it's best to be among complete strangers, ironically enough.
The trick lies in determining just when you need to shift from relying on others to relying on yourself. Just exactly when can you trust that you really are having a good day?
I'm still working on that one. I think we all are. If you figure out, let me know.