I love hand quilting and machine quilting. I was absolutely terrible when I started hand quilting. I really struggled with getting the knot through the fabric too! What I do now (which works most of the time) is to hold the quilt behind the knot as I pull in the other direction. I am currently doing big stitch quilting using perle cotton thread, which is thicker than normal thread, so the knot is bigger too. I haven't had any problems so far! I also sometimes get a problem with the knot at the end, so when I try to pull it through, the thread breaks off at the knot. Very annoying because you have to undo enough of your stitches to be able to try again. My advice for that is to make the knot slightly smaller than the knot you used to start off (eg. I usually make a quilters knot with 3 wraps around the needle to start off, and will just use 2 wraps for the finishing knot) and this usually works pretty well!
I got a lot better at handquilting after I found "thimblelady". I bought her book and thimbles and worked through it on the practice square that she sent with the book. Went from massive, wobbly stitches, to nice even ones in a couple of hours. My stitches still aren't perfect, but I'm happy with them! Her thimble is the first one I've actually been able to use as it has lovely deep holes to hold the needle! You have to order it from Australia, but in my opinion it was totally worth it!
Sorry, haven't got much advice on machines but thought I might be able to help a bit with the hand quilting!
Good luck!