Any tips on deciding on who to breed this March?...I am fairly new to chicken breeding and am still learning.
I don't know what traits are important that breed, but here are some ideas that can apply to any breed:
Pay attention to temperament. Think about whether you want to deal with this particular bird for however long you intend to keep him, and consider that his chicks might also grow up to act like him.
Pick up each one and give him a thorough physical checkup. Check for things that are harmful to the bird (like crossed beak) and things that are just undesireable (like a crooked tail) and even for things that could be treatable (like bumblefoot). You may find a good reason not to keep one or another of them.
If you raised them from chicks, think about whether any of them needed special care as a chick (maybe one had pasty butt and the other two didn't.)
Check breed-specific things. You can usually look up a list of basic points like weight, comb type, number of toes, feathered feet or not, crest or not, skin color, and so forth. Points like body shape are harder to check against a list, and I can't personally help you there.
Think about how quickly they have matured (crowing or mating), and whether early maturity is important to you.
Consider your hens as well-- if there is a particular trait where your hens are lacking, try to pick a male that is especially good in that area.