This is obviously not a cut and dry problem. There are multiple factors involved, which I will cover in future posts.
I believe one of the main factors in the lack of success in many individuals' training programs is a lack of training basics and fundamentals. A house is only as good as its foundation and a house built on sand will not stand. Lets face it: the basics are not sexy but if you want long term success you better build on them and work to maintain them.
Here is one of our basic general warm ups that we use to get people started. It is a mishmash of stuff from Martin Rooney, Bill Hartman and Mike Robertson. We have watered down many of the drills to meet people were they are.
From there we teach the squat and the hinge. When we have that down we progress into a general strength training program for most people. With out a good solid base your chances for long term success are greatly reduced.