It all comes down to deciding what you simply have to have. Look at some morphs, decide on a direction you want to go, and choose accordingly. I got my morphs knowing that I wanted blue eyed leucistics, whacked out patterns, and calico anythings. So my breeding collection is now 8 strong (plus 2 pets that I don't intend on breeding) with spider, pastel, pinstripe, mojave, lesser, cinnamon, calico, and albino (unproven het) in my gene pool.
I knew what I liked, found what I wanted, and am satisfied with what I currently have.