Ok. There are a lot of extensions that will help you on chrome. They catagorize the rarity of certain traits. There are also calculators in which help determine offspring (I had to try and decode the genome when the game first launched, took hours and hours to figure out some cats, now it's easy). Anyways, install the browser plug-in (I personally like the one tampermonkey one), it is prestty easy to install on the browser, just search cryptokitties in the chrome store.

Early generations are better to buy and hold. When you breed cats, their reproduction speed goes down. Earlier cats that have slower regeneration still hold some value. Later generations with slow regeneration are almost worthless, as the new cat will take on it's slowest parents speed.

Id suggest getting a quicker, earlier generation cat, bred it to produce offspring then sire it when it is slow. That should give you the best return. I would love to keep playing, just don't have the time. A lot of fun nights with the wife making money!