I taped two plastic forks to the work surface in my craft room. I can tape them farther apart if I want to make a larger bow.
Then I started looping the ribbon around the tines of the fork.
Criss-cross the end of the ribbon and tie a knot.
Slide the whole thing off the forks, and there is your bow. I know, it is still not the prettiest bow ever, but this method did help me to hold things in place while I worked.