those look quite good
Nice job GLBM I like the way you've incorporated the marble.
You do have skill with knots, friend, you just don't realize it yet. They aren't difficult to learn to tie, it just takes practice like any other skill worth learning.
Stormdrane puts out good stuff on YouTube. Don't be afraid to pause the video or rewind- sometimes the knot isn't intuitive, but you will get it once you get some practice with it.