Rafael Elizondo is a fabulous Mexican concert guitarist who has been making wonderful videos for his youtube channel. If you don’t speak Spanish, you may not be at too much of a disadvantage because he demonstrates everything very clearly. This instructional video below is a fine example of Rafael explaining how to use fixed fingers to establish stability and confidence in the right hand.
Here is another great one where he demonstrates 4 finger coordination patterns for the left hand:
Check out and subscribe to his channel. There are tons of great posts.