If you've already taken some lessons, I can't suggest much. Maybe: to take great care to taxi correctly... it is one of the harder skills to master, and it's important to learn to do it right.
One thing I learned when I got into old taildraggers that is useful in any plane is that "brakes are for stopping, not slowing down."

Another thought: at some point, ask the instructor to use the chart to cover the entire panel, then let you try to hold heading and altitude in a few shallow turns. That was one of the most useful exercises I was put through during my primary training; teaches you how to fly smoothly while looking outside 99% of the time. It's fun, too.
If he says "no", say "OK- how about a spin, then?"

(just kidding with that last one, but it can't hurt to ask)