The way we used to do it is to smoothly comb
wet hair all up into a high ponytail and then comb the ponytail smooth, wrap it around a tin can with both ends cut out, bobby pin in place, and let it dry over night. you can wear a headband or scarf to keep your edges smooth. We use to use Dippity Do but you can use some other mousse or gel.
Another way is to comb each section smooth, and set it on really big velcro rollers.This won't end up being pin straight, but the diameter of the curl will be bigger.