I like to explore new lakes, rarely fish the same lake except the local pond. Here are a few tips,
1, point and choke
in the lake map, if there is a point project in to a gradual deep water, it is a good spot. close to any narrow choke area, it is a good option. Don't take time cover water, try point to point if mobility is not an issue.
2, Prediction
In the early May or late fall, searching fish from shallow to deep. Make the adjustment quick. If there is not bite in 10-15 min, move a little deeper. keep the fly close to bottom
3, using indicator
there are only two pattern you need, a size 14 micro leech and a size 14 zucchini chironomid. The indicator will hang the fly constantly in the strike zone. offer the fish more time to find your presentation
4, adapte the weather.
avoid huge wind and no wind. windy condition is good for lake fishing, but not the two extreme
5, no more than 30 feet
thought in specific lakes and in summer time, people have luck in deep water, the depth more than 30 feet is not suitable for fly fishing IMO. You can screen the deep lake out of your fishing destination at the beginning. When the fish are deep, usually it is time to fish in the river.
This is my third year lake fishing. I have explored 80+ lakes in Kamloops and Cariboo area in spring, fall and winter. I don't remember any one time skunked.