Here is a couple period examples for inspiration. This style could easily be worn with a hairnet, like the photo on the left.
This is a nice style for medium length hair, and works especially well if it's thick.
Start by parting the hair down the center, and then braid each side. I had to re-braid each side once because I'd started them to far forward, causing the braids to be too short.
You want to get the rubber band as close to the end and possible, or if the hair is long enough, you can make the ends into a little loop. Also, neutral colored rubber bands blend in nicely.
Next, take the end of one braid, and tuck it under and into the base of the other braid, secure with bobby-pins.
Do the same with the other braid, going underneath the first one. I put most the pins on the underside, using the rubber bands to get a hold of the ends.
Instead of blossoms, a large bow or hairnet also look great. Use your imaginations! :)