While a paddle is great on a river, the only way to navigate a small to medium sized bass lake is with a motor. It took me quite a bit of time to find the perfect mount - reliable and cheap. Surprisingly, I found this at LL Bean. I normally associate them with more expensive goods - but this mount only cost $50 two years ago and is actually cheaper now - it's $49. Amazon now carries a pretty good selection as shown in the links below.
The principle is simple as you can see from the picture below. It's just two pieces of wood that clamp together using heavy duty bolts with a big wing nut. You jam the mount as far into the back of the canoe as you can. The two pieces of wood end up following the rail with one on top and the other on the bottom. Once positioned and straight, you screw the wing nut down. I find it helpful to take a pair of channel lock pliers with me to give the nut an extra pull. If the nuts are too loose, the mount will slide off.
My trolling motor came with a nice set of clamps as you can see from the picture at the lower right. Mounting the motor to the wood is as simple as screwing it on. Bingo! You're in business in about 2 minutes!
The only tricky thing is that the new seat sometimes gets in the way of turning the handle if I have the motor down too far