One tip I have is I like to tack my seams together or the sides of a pair of HSTs when I am joining them. When you are working with minis every little thing is magnified. so a 1/16" off looks like a half inch off. I match up my seams and run a stitch through them twice. Then I look to make sure the seams are matching before I sew the HSTs together.
A stitch in time saves nine! LOL It does save frustration later on.