Keep practicing with the new tube. It takes a while until all of the maneuvering becomes automatic and you can concentrate on just the fishing.
There are lots of small lakes and ponds that are ideal for tubing. The ones that restrict bigger craft are great, but even some that don't can provide some good tubing and tooning. In fact, there are a lot of big lakes that have small arms and coves that you can fish just like they were small lakes. You don't have to cover an entire lake to have a good time and catch fish.