I am not enamoured of turning ties or straps for an apron, or anything, if I don't have to. So I made the pointy ties for MrsDrWho's Lotta Apron without a turn at all: just an iron and some folding!! Here's what I like to do:
First, catch your strap. Decide the finished width you desire, or the pattern specifies, and cut your strap 4 times that width. So, if I want a strap 2cm wide, I must cut the strap 8 cm. Here's where you decide to be a pedant like me and cut off your selvages, or just leave them be and have less bulk at the point.