With knots: if you get a knot that has a loop in it, try stick your needle into the loop and pulling it up. this is hard to explain, but basically, let the knot part hang down from your needle, and use the needle to pull up on the loop part. Sometimes this helps.
Source: Former very serious cross-stitcher and occasional embroiderer. It's fun the things you learn other people used to do, isn't it?
I like how into crafting you are. I am going to work on my decoupage post now. I feel bad for having not.
I second jadedog's recommendation for beeswax, though I have learned this more from book binding than anything else.
Also seriously, just get you a trillion needles. Sewing needles and deodorant are similar in that you can never have too many of them scattered about your house.
Also I am hoping you can provide a nice close up picture or two of the backstitch, that is the only part I am having trouble conceptualizing. Can you talk more about that?
Your stitches just straight are big, but hey, who cares that much? First try!