It's a bit late in the year, but my tip is to time your lap splits, especially the first several races of the season, but if you're in the habit of doing it you might as well do it every race.

Number one mistake (IMO) is thinking that you paced a race correctly simply because you are passing more people than are passing you toward the end of a race. The clock doesn't lie. If your laps get slower and slower over the course of the race, you started too fast.