HSTs, since they're cut on the bias, do tend to get distorted with steam and handling. So keep that to a minimum. Also if the pattern says cut a square to a size such as 4 7/8, many of us simply round up 1/8 for wiggle room. My HSTs turn out better that way.
I have been known to make several too small, by the way. Instead of redoing, I just cut the squares to same size as the HST. I wasn't following a pattern so as long as my blocks were the same size, everything was going to be fine in the end.
You'll also find that once it's quilted and washed, the points won't be so noticeable. You'll like the thing so much it won't matter, and can simply look forward to getting better with practice. I tell myself I'm not as good as I want to be, but better than I was a year (or two months or whatever) ago. It's gratifying to see one's own work improve with each quilt.