Good advice on this thread.......
Lifejacket is a must, get a lightweight inflatable that's comfortable, put it on and keep it on.
Make sure you can get back in the boat if you go over, ride motor up, roll up ladder, what ever it takes, just make sure you have a way back aboard.
If you were to get injured, go over, and cant get back in, put your phone in a spot you can reach it if necessary. Put it in a zip-loc if you have to, just make sure its reachable if you need to get to it. I fish alone a lot and have ever had an incident where I needed help, but before the trolling motor goes down I make sure I'm prepared to contact someone if I do.
Preventive maintenance, make sure all essential equipment is in good working order, doing on the water repairs is a lot harder if your alone.