When tracking initiative, also track the round.

In my games, I use my DM screen was the iniative tracker. At the top of the tracker, I stack 5+ pieces of paper that are labeled 1-5. Whenever I'm at the top of the initiative tracker, I'll remove one of those pieces of paper.

Why? It's important to keep combat relatively short (3 rounds +/- 2 is ideal).. it's a great reminder for triggers, like adding or removing enemies or having other events occur