I now spread my feet on the approach 3 - 4 inches from one another, it gives me a stable base and helps me to stay solid at the line.

I think the back hand is the best way to pick up the ten pin, it is so easy just twist your wrist to the right and you are instantly a left handed bowler. It is almost like cheating, or a trick shot, also remember practice makes perfect.

You will not learn all the bowling tricks in the world by yourself. Nobody can ever learn from one's own mistakes all the lessons he needs to learn. The tip is to get a professional coach/instructor from the very beginning before any bad habit is developed. So you can focus on proper techniques when you practice your bowling, and then you can expect a constant improvement on your game all the time, instead of reinforcing bad habits.

I used to try and flatten my hand with my strike ball until I went to a bowling clinic with Liz Johnson and her coach and they said I should be using a plastic ball for all my single pin spares.

Most coaches will have you work on several aspects of your bowling style to assist you in raising your average.  While that's necessary to a degree, I believe in helping bowlers with, what I call are the three most important things in bowling,  Accuracy, Accuracy, & Accuracy!  Sure there's a ton more to the game but having a person concentrate on being accurate will ultimately help them improve several aspects of their game.  Having been a coach for over 30 years this point has worked well for the hundreds (if not thousands) of kids and adults I have worked with.  Work on accuracy first and a little of the other points along the way and your average will increase.