That's a great question. Since I don't produce every available morph, I can't answer your question with 100% accuracy. But I've noticed some trends over the years:
1) People like color. The sales on snows and anerys seems to be especially slow the past couple of years.
2) If you're excited about the snakes you work with, your potential customers will be too. Excitement in contagious - don't work with a morph because it "sells well," breed it because you like it.
3) Selectively breed. Hold back your best babies. If you have the best Reverse Okeetees on the planet (or whatever morph floats your boat), customers will find you and buy from you. Take pride in your work.
4) Get a camera. There's some good digital models out there for as low as $200. Take quality photos of individual offspring for sale as well as their parents.
5) Have a website. With a website, people will conclude that you're "for real" - not just some guy or girl on the internet selling stuff.
6) Get a classified account at kingsnake.com. I sell ALL my snakes via this website - I haven't been to a show in years. I love this place!
7) Provide good customer service.
Don't make the same mistake huge numbers of Ball Python breeders did - work with a morph because it's "hot" and then not understand what they couldn't sell their offspring. Selling these days is more than just producing babies for the market.
Follow the above steps and you'll be a few steps "ahead of the game" of making sales.
Tim

Third Eye