finding small mouths

Anyone got any tips for finding small mouths when they are not off the rocky shore lines and points? I am kind of new to fishing for these fish, and have had some good days fishing off rocky, shores with large boulders, but when they are not there its been poor fishing. Pend O'Reille has a lot of rock faces and cliffs along the shore, but they have not worked out for me, or has more gentle sloping beaches. I have had no luck finding suspended fish in deeper water. The lake is vast so obviously I have not searched much of it. But if you have any tips that have been successful, I would be happy to give it a try. Thanks.