I've washed my kitten with this flea shampoo and I still see fleas in her furr... should I just wash her again or what? This has happened before

You can't use it any more than the shampoo says or you could poison her.

Get a bowl of soapy water a fine toothed flea comb from walmart... etc and pick them off drop them in the bowl of water and drown them. A vet will sell you a good product depending on the cats age... you should be able to walk in and buy it, just let them know how old it is.
Also you need to vacum your house everyday, if you use bagless take it outside to empty into an airtight bag and throw away. If you use the bag type it is recommended that you change the bag daily. I have heard of people putting flea collars in the bags and sitting them on the porch until the next use.