As far as the actual print of the fabric goes, if the pieces are smallish, you cut the fabric so small the print is sort of lost and you just get the effect of the colors. In this case I would just avoid animal prints, you don't want the wrong end of the horse to wind up in an awkward place.
If the pieces are larger, then they play more of a role in the quilt. Prop up the bolts of fabric on the floor or counter and view your selection from at least six feet. You can see how the prints play together.