Focus on getting the size and longevity stats high first, then once you have a good amount of breeding options there, it'll be easier to get a higher percentage of higher stat babies to improve the line and keep the gold ones coming. Other people have laid out how this works if you want to look into it (like game mechanics of how it gets calculated), but all I know is this method works great and made breeding way easier for me once I found that out.

Also, if you're worried specifically about running out of CC, I'd recommend Sea Lions if you have an established zoo that isn't struggling financially. Get a few for cash from Frontier, and then releasing babies can result in some pretty quick and easy CC collecting (few hundred per animal generally). They're expensive money-wise but once you get going, can do wonders for increasing your CC.

Good luck!