I made a bunch of small items (mostly potholders) to practice on and try out different techniques and found the ones that worked best for me (so far — there are probably new ones I could try that would improve things more). As Garden Gnome just said, “Everything you do is subject to change if you find a better way to do it.”
I did a lot of Googling and reading. A couple of the things I learned made light years of difference. Squaring up the blocks was a biggie, as two people have already mentioned. Chain piecing helped me to sew straighter, since I was often veering off in the last inch or so. HSTs (and some blocks) can be cut a little larger than needed and then cut down to size.
There are a lot of different ways to do binding. I wanted to find one that could be 100% machine sewn, and I tried a lot of different ways before I found the one that works best for me (or rather, one that wasn’t a complete disaster).