I've been at that point a couple of times. I'm pretty well out of Samoyeds .. have only a young male in the house.. coown a couple b*tches and now need to decide if I'm going to start "breeding" myself again or just ride on some co-breedings. I also within the last 6 years went into Bernese and had to find a foundation b*tch I consider worthy of working with.
Things I considered:
Work ethic- If the dog can't do the job it was bred for it is WORTHLESS to the breed.
Pedigree
Consistancy: Ability to reproduce a HIGH percentage of HIGH quality pups (its far better to produce 50+% show quality pups than 25%... and the overall quality of the litter is higher as well... I do NOT want to deal with the ONLY show pup in a litter of 10 EVEN IF it is phenomenal... simply because it is unlikely to reproduce a high percentage of high quality pups)
Genetics: I investigated 10 generations of the pedigree AND found as much information on related dogs NOT on the pedigree as possible. Its great if all the dogs on the pedigree have been OFA'd CERF'd etc... but if their siblings couldn't pass or weren't even checked how do you know what YOUR dog will produce?
Indepth knowledge of the weaknesses of the line- The Sam I have now comes from a line known for weak rears... *he* has a superb rear. My Bernese girl comes from lines known to have less furnishings than other lines.
Performance of the line with other lines- Seriously, if you cannot breed it anywhere but to the same line without getting a ton of ick how on earth are you going to continue to build improve the faults your line has?
You have to have a clear vision of what YOU believe the breed is meant to be... the parts the standard doesn't spell out. You need to figure out what is most important to you and how to keep or achieve that. For me... its all about whether the dog can work AND still fit the standard and win in the showring. But first its about the purpose of the breed...
Its often difficult to find breeders who are willing to share the dark secrets of their lines. But if you listen, take notes (even surreptiously) you can glean a whole lot of information. You also have to be able to do deductive reasoning- ie: the dog that has multiple Group and BIS wins but never has an OFA number probably has an issue ...
You also have to be strong and not waver when the naysayers don't understand why you chose a structurally strong b*tch who is a bit plain as a foundation b*tch rather than the flashy show winner with the structure faults and the cute face.
ALWAYS choose structure and ability to perform the job over flash. You can add flash and coat in one generation. Fixing structure faults is a multi-generation thing.
Edit: For Samoyed Lover: There is not a single responsible reputable Samoyed breeder in the US that will sell a puppy at less than 8 weeks of age and more likely 10 weeks. The SCA requires a minimum of 7 weeks and THAT will probably be revised very soon. I also know VERY VERY few reputable responsible Sam breeders who EVER use their own studs... it is so very unlikely that their stud would be THE BEST dog to be bred to the b*tch and great breeders are all about producing the BEST. My grandparents bred Sams.. I've been breeding them for 19 years... the only reason I'm not breeding now are my own health issues.
Editx2: bellacav: AMEN!!! great great advice.
Editx3: apparently Samoyed Lover has removed her answer...