To expand on Laura's answer a little there is a general scale of points with minor differences for how colored birds are judged vs white birds. In addition certain specific breeds also call for variation from the General Scale.
These include Crested Breeds, Modern games. Malays,Aseels, Shamos, Japanese Bantams, Hamburg & Rosecomb Bantams, Buttercups, La Fleche, Yokohamas & Phoenix.
Owning a Standaed of Perfection is absolutely necessary if you plan to show & hope to win.
I also always recommend going to some shows before you buy anything. Look at the breeds you're interested in & see what the winning birds look like. Talk to the exhibitors showing you selected breed or breeds. Most of us will talk all day about our birds. After you've done these things & studied the Standard then you're ready to buy birds.
Lastly, you'll be better off if you decide on one or two breeds to focus on. Many people try to breed several breeds all at once. This is hard to do successfully, especially for a beginner.