There are many factors that go into correctly pricing your tickets:

1. Location of your seats:

The location of your seats is one of the most important factors in determing the "fair market value" of your tickets.

2. Box office price of your tickets:

The price that the box office charges for tickets that are purchased directly from the venue.

3. Your competition on the site that you have your tickets for sale at:

Whether you are selling your tickets on StubHub or Craigslist, you must be able to compete with the other people selling tickets to the same event.  If you are asking too high of a price, you won't get any calls, if you charge too low of a price, your tickets will be quickly bought, but you will miss out on making more money on your tickets that you sold.

4. The Teams that are playing:

Division rivals and the leaders in each division tend to be large crowd draws.  In Baseball, the New York Yankees, Los Angeles Dodgers, Boston Red Sox are among the leaders in crowd attendance when they are the visiting teams.

5. Day of the week:

Weekends typically will have the larger crowds, with mid week Day games drawing the least amount of people.

6. Day or night game and weather predictions:

Night games during the week will usually not draw as good as Friday and Saturday night games.

7. Time of the sports season:

The first homestand of the Major League Baseball season will usually have higher than average attendance.  The last homestand will usually have better than average attendance as long as the team is in contention for the playoffs.

8. Who is your competition?:

Top tier teams will usually outdraw the other teams who aren't in contention.  Each team will always have some of its fan in attendance at your home games.