This might be the first really light airs since you've all been sailing on your own, so hopefully you need to be aware of the issues. Did you notice how, even when the wind did blow a little, some patches of the lake were covered in ripples and others were glassy smooth? This sort of erratic patchy wind is typical of Summer days and especially evenings. There's a wonderful book on (amongst many others) this subject you can get from the library, called "High Performance Sailing", by Frank Bethwaite, which goes into all this stuff in far too much detail for me to really comprehend, so maybe you don't want to get it out this week either!
If you look around you will often see that the wind is blowing in different directions on different parts of the reservoir. Having a sensitive wind indicator is important and you have to really think all the time about what the wind is doing and what you think it will do next - watch the boats near you especially those upwind of you. (Remember to watch boats behind you if you are on a run).
Key Factors in getting the best out of your boat are:
Now in these conditions you get very little feel and very little feedback, but changes in speed can be very obvious, and balance is critical. The most important thing you need is patience. Keep very very still : you'll feel the tiniest puff of wind better, and you won't disturb what wind there is getting over the sails.
With balance one rule changes. Normally you want the boat absolutely bolt upright. When its really quiet you should let the boat tip 15 degrees or so to leeward - away from you. In a singlehander this means you will be at best in the middle of the boat. The reason for this is that gravity will move the boom over and fill the sail in the right shape. In light airs it doesn't take much to stop the air moving, so if your sail is already the right shape all the wind will be pushing the boat, not wasted in trying to fill the sail.
Another thing that can surprise you in light airs is coming into a jetty - a boat like an Enterprise will take far longer to come to a halt on a light day than a windy one. That's because its the wind blowing on the flapping sails that slow you down: if there is little wind then there isn't much slowing. Allow about double the distance to slow down when approaching something solid.