Most stallions are only going to have minor, picky conformation flaws (from perfection) that are overcome by their race record, but you consider when breeding to your mare to them.
"The faster they run, the prettier they get"
Bloodhorse has an excellent small basic conformation book for yearling sales. If you go on the internet, there are lots of equine conformation sites that have good pictures. You can see pics about obvious things like over at knees, toed out, etc. and you can indeed see that type of thing in the paddock esp. with lower end horses.
Go watch the walking videos of the stallions advertised on the farm websites - that will help show you good walks.
You really only develop your eye on live animals, but you can certainly learn the basics from a book and photos.
Seabiscut was noticably "over at the knee". Go find a picture of him?
