The information below is a collective from parents. Please do your own research, and always consult with a physician should your child have any type of allergies, or other health sensitivities.
Girls with hair long enough to braid, should do so, every single day.
SHAMPOOS/CONDITIONER
Tea Tree Oil Shampoos & Conditions may be helpful in preventing the transmission of lice. Lice simply do not like strong herbal aromas of natural essential oils such as tea tree, eucalpytus, lavendar or rosemary. However, NEVER ever put an essential oil directly on your skin or your child's skin. Direct contact can cause skin irritation.
Koo-dies Shampoo (Pacific Holistics) with NEEM (no toxins), Natural and safe is available at Point Loma Drug.
Purchase products that have these oil infused in them instead. Many stores like: Henry's, Trader Joes, Fantastic Sams, Fresh & Easy, Vons, Target, etc. carry Tea Tree Oil Shampoos & Conditioners.
SPRAYS
Lice B Gone™ - You may use this spray in conjunction with treatment, and as a preventative measure.
Or, you can make your own spray. Here is one easy recipe:
Take an empty hair-spray sized pump bottle.
Fill it with water.
Add about 20 drops of pure tea tree oil to it. It's available at Henry's and most drug stores. This is pretty pungent spray. It's safe to add more drops to the mixture if you'd like. You never want to apply pure tea tree oil directly to your child's skin. The pure concentrated tea tree oil can cause irritation. But, in the watered down spray version it is absolutely fine.
I ran out of tea tree oil last year and made my mixture with pure eucalpytus oil, which is even MORE pungent. It will keep lice AND friends away. :) You only need about 5 drops of this oil. Incredibly strong stuff.
If you have a girl with long hair, spray the hair down lightly with the spray. Then braid the slightly damp hair. Put an extra squirt at the base of her hairline. If a jacket or backpack get a critter looking to hitch a ride, the nape of the neck may be the first 'path' to her head.
If you have a boy, it's even easier - just spray, work it in, and you're good to go.