SAVE! save save save and then save some more. cut expenses where you can (not too much so that you are unhappy because you will then stop cutting expenses), have a big pile of money then start investing. if you only have 1K and want to invest now keep expenses as low as possible with 1 pick and go with it.
Personally I've found the psychology of investing the most difficult to master.
Seeking wisdom by peter Bevelin or the munger psychology of misjudgements speech are both very good.