Being a fairly new breeder myself, it can be a daunting task trying to sell your kitties. There is a great trait chart here on the forums, use it

It has great information and will show you just where your traits are in relevance to their recessiveness. There are many ways to sell your kitties. Bid boards have been mentioned and they can be found on quite a few of the sims that offer Kittycat auctions. These are usually an inexpensive way to sell your kitty and will last 24 hours. Most sims will advertise their bidboards, and attract buyers looking for specific traits. Auctions are another option; however I have noticed that some sims are very particular in what they sell so before you buy a panel try to talk to the auctioneer first, or attend a few auctions, see what is selling, talk to other breeders. Higher traited kitties usually sell best at auctions and most look for 7+ traits; in some special cases auctioneers may allow lower traited kitties if they have a very special or new trait.
If you plan on breeding as a SL business or just for for fun, you may at some point invest in a small shop on a sim, and in some form of advertising. This can help sell your kitties as well. As with any large group of people, virtual or real life, there will always be personality conflicts. So find a group that you feel comfortable with, make some friends in the KittyCat community and have fun!