I Need Preventive Ways To Keep Fleas Away From My 8 Week Old Puppy?

I just got an 8 week old puppy from a friend and he had fleas, so I used tea tree oil shampoo and drops to wash him and the fleas have seems to go away, but does anyone have any tips on how to keep them from coming back and what I can use on my furniture to make sure no fleas are there.( keeping in mind I have small children and a puppy around) thanks.
ps. he is too young for flea treatments