A few additional pointers:

Record yourself. This is the reality check you must do. Don't be too bummed out if you dont like what you hear, but decide what it is that you don't like, then re-record and listen again. Keep doing that and slowly but surely you will hear improvement.

Practice, practice, practice! A good place is in your car with backing tracks you've created for your tape or CD player.

Good luck, better yet, keep practicing!