The way I always spool up is with an old fishing rod cut down so there's only the one guide closest to the reel seat left. I put the spool of line in a cardboard box with a dowel rod through the box and spool so that it sticks out about 2" on each side. I run the line threw the single guide and use my sock feet on the dowel to apply pressure, I still have to thumb some of the line in place but 9 out of 10 times it goes on perfectly.

My casting reels get an extra step... I tie them off to a fence post and rewind the line under super heavy pressure to minimize backlashes and better longer casts. I use to just slap the line on kinda loose and then tie it off to a fence post, and that worked okay too. When I know I'm going to tie it off, I always over fill the spool and then just cut a few yards of line off to maintain maximum capacity. 

I can't help you with spooling spinning reels... always been a big mystery to me