This arrangement of Roll in my Sweet Baby's Arms is all cross-picking and has some difficult string crossings. Take it slow. Measure 2 is repeated, almost note for note, 3 times. This would be a good measure to loop and build up your speed. This makes your practice time more efficient instead of trying to play the entire arrangement over and over. Always isolate and focus on the hard spots. Especially if they reappear in the arrangement.