Watching good players is useful, but you may not know what you are watching and then it is less worthwhile. It is best if there is good commentary on the match. If the commentators don't seem to make much sense or say anything useful, move on.
Get books by Byrne, Alciatore, Martin, Fels, Capelle. Just stick "billiards pool" into Amazon book search. Dr. Dave has lots of help for pool students on his site at http://billiards.colostate.edu/
This is so true! I have a very vast accu-stats collection and have watched videos religiously (off and on) for years. As I improve my knowledge base I keep getting more and more out of them and have also had to learn how to watch them.