Footwork and finding angles for punches

Depends. I wouldn't necessarily try to copy mayweather, as his moves are a lot more subtle and nuanced than they appear. Moving forward with his left foot at a 45 degree angle entails several other factors which are far beyond a beginner's grasp. As for general advice, just work on your technique. Shadow box (in front of a mirror), jump rope, work on your movements and pivots, and of course spar. A lot will come in time.