Selecting the Right Stud Dog
When looking for your bitch's Mr. Right, you need to make many of the same judgments you did when you evaluated your female. Any male dog used at stud should be at least two years of age and have the expected health clearances that are standard for your breed. Virtually all breeds should have basic orthopedic clearances, up-to-date eye checks, and current thyroid level testing. Any dog with a serious genetic defect, including ones that aren't easily noted (such as epilepsy) should not be bred! You should ask to see the clearance certificates and the stud dog's pedigree. A responsible stud dog owner will want to see all of those things from your bitch as well.
You should meet and evaluate the stud dog in person ahead of time. This lets you evaluate his temperament and look at his structure. Ideally he will have been shown successfully and done some performance work, earning titles for his expertise.
Again, if you are a novice, ask for the opinion of a respected mentor, especially if that person knows your bitch as well. You want to be sure you don't double up on any undesirable traits or health problems. This is where studying pedigrees and following dog family lines is invaluable.
If possible, try to meet some progeny already produced by the stud dog. Evaluating them will give you an idea of what traits he may pass on. Always factor in the bitch's contribution, too — so try to look at puppies or dogs produced from breedings done with bitches similar to yours.