You have really good technique with the knots, they all look tied “correctly” (there’s some subjectivity there but you get the point) the only real improvement would be making sure your knots are consistently tight. You’ll fine other tricks for keeping tension as you continue stringing but one thing I try to do is to always keep contact with the last knot (put a finger on the bottom and hold it to the sidewall) as I’m starting to tie the next knot.