Jay is right about this, mate.... There are only two ways to tie a knot. Exactly right and hopelessly wrong. You should practice some more with a fool-proof knot. It will be the method you can always fall back too when things get hazy or unclear. Everything gets easier after that when you try different knots like VT and such.I teach occasionally, and no-one gets to lift their asses 1 foot off the ground without being able to tie a double fisherman's knot, prussik and bow-line behind their backs.
When it comes down to it, there are only two things whom are actually necessary to climb a tree and that's a harness and a climbing line. Explore that method in case you lose some equipment when you're up there...