What are some good techniques when fly fishing a ...

Fly fishing a lake from shore can be tough.  I'm going to assume you're fishing for trout.  The first thing I do when fishing a lake is to stand back from the shoreline as far as necessary and just watch and listen.  Trout in lake many time cruise the shoreline looking for food.  Stomping right up to the edge of the water will spook many catchable fish.  Trout in lakes, more so than in streams, are very wary.  They have to constantly watch for predators above and the shoreline.  This means you have to approach the lake very carefully.  Even to the point of crawling at times.

 Often times you will have to sight fish and cast to cruising fish in lakes.  So work the edges outwards.  If you aren't seeing any cruising fish, looking for structure is your next step.  Structure like downed trees, boulders, and dropoffs are great places to start. At this point you'll be casting blind to areas and not specific fish.

Get out and try it.  The more you do it the more you'll learn about fish, their habits, and their habitat.  Enjoy!!

Aim for rising fish. Common lake hatches are damsel flys for which there are patterns as well as small black midges which can be imitated with a griffith gnat pattern. Sometimes just lobbing out a big attractor pattern such as a stimulator or a royal wulff will attract fish, it helps to give the fly a few twitches and make it "dance" on the water. I use floating flyline for this method. Yes...fly fishing can be exciting!

If there is no action on top I usually use sparsely dressed woolly boogers (no bead head) and soft hackle nymph patterns such as a pheasant tail (obviously) on an intermediate sink tip line.

Cast out and let the line sink occasionally twitching the rod tip.
Retrieve the boogers with slow strips and pause between each. The nymphs I allow to settle and then slowly raise the rod tip and "hand-line" the retrieve, the slower the better.