The Mavericks enter and leave the court through a tunnel that is located above section 103 and between sections 102 and 104. For a good chance of seeing the players enter and exit the court near this this tunnel, you will want to try to find seats in the closest rows to the court in these sections (which have lettered rows, so the closest to the court will be row A).

The Mavericks bench is located behind section 117, which would also be a good place to sit for being located near the players.

American Airlines Center view from Section 102 Row D
The view from Section 102 Row D is shown above, the Mavericks players come from the tunnel directly to the left of this section.