
The best person to advise you first off is the breeder of your bitch (assuming they were knowledgeable and reputable) as they will know their lines the best, adn will also know the lines of suitable mates.
If you dog/bitch is not from such a breeder it is very likely they are not of the quality to be bred from, but there is nothing to stop you enjoying them as purely a pet.
Join your Breed club and ask to purchase the current and back issues of the8ir club publications for say the last 10-15 years. Thes will allow you to study how the breed has been developed by various breeders, hopefully breeder adverts will icnlude moet of teh influential dogs and bitches in your pedigree.
Attend shows and/or working events for your breed, read good breed books, and obtain the Book of The Bitch for practical general advice.
Good luck with your research, it is fun, but can become pretty adictive :D