References are always good, some breeders are more than happy to trot out with letters from previous buyers stating how happy they are, and give you their phone number so you can contact them. Use all your senses at the breeders(well...I wouldnt expect you to taste the kitten...or the breeder rofl), including your 6th sense! Does it smell like feces/urine? Does it look clean? Do all the cats seem healthy and happy and friendly? Do the cats and kittens coats look and feel shiny and healthy? Are the cats caged or are they treated as family pets and loved? Are the kittens well socialised? Do you get the feeling somthing is "off" about the place? Does the breeder actually CARE about where their kittens are going? Do they interview you as much as you do them? Many good breeders will offer health guaruntee's, you usually have to take them to the vet within a certain amount of time of picking it up though. How old does the breeder let her kittens go at? Anything under 12 weeks could be iffy, they need that time to socialise with their littermates and mother. Ask what vet they use, contact them and ask the vets honest opinion on the breeder. Ask the breeder to explain what to look for in a good quality Ragdoll, do research prior to make sure they know what they are talking about. Ask if they are in favor of declawing, if so i'd reccomend getting the heck out of there and finding a new breeder with a heart and brain. You may also end up waiting months for your kitten, be prepared for putting a deposit on an upcoming litter than waiting 3 months after its born to pick it up.
I know this sounds like a lot, but when you consider you are going to be shelling out tons of money and twenty years with this cat it makes sense to get it right. Expect to pay a lot for the kitten, and count on paying even more for their shots/neutering/spaying (We bought Envy from a breeder, her shots/vet visits alone cost us almost an extra $300 the first few weeks, and her spay will be even more)
And last but not least...Good luck on finding your new furrbaby! Be sure to keep us updated and post pics as soon as you get him/her!!