Just keep one thing in mind, that is do not give up and have patience. This is not something that happens overnight. Take it slow, selling on eBay and free or inexpensive marketplaces at first. Try Etsy, Ecrater, Bonanzle, and Shop Handmade just to name a few. Once you have gotten your name out there and started selling at a good pace, it is a good time to make a website. If you are impatient and want one sooner, making a website that is inexpensive will be a good idea at first. This way you can monitor how many visitors you actually get before upgrading to an ecommerce site. A good company to do this with is VistaPrint. There is a link for them to the right of my blog, you can get a basic website for $4.99 just to see what the response is. When you upgrade to a site to sell on, VistaPrint has a $19.99 a month plan that is wonderful! Now is when those mailing addresses you have from all those orders will come in handy. VistaPrint also has tons of marketing items, and one of them is postcards to match your website. Order some postcards and send them out to all your past customers to let them know you now have a website.
Once you are getting orders at a good rate no matter where you sell, you know you are doing good, and making what the customer wants, it may be time for you to start selling your diaper cakes at craft shows. Craft shows are very fun and very addictive as well! Be sure you order plenty of business cards and a banner with your business name and website address on it as well, also all available from VistaPrint.
Another way to sell your cakes is by selling wholesale to stores such as baby and maternity boutiques. Make sure you dress nice, act professional and are prepared to answer any questions the owner may have for you when you go.
Lastly, good luck and have fun!! Resource links below!
How to Prepare for an Arts & Crafts Show
Being Successful at an Arts & Crafts Show
Well I just got done searching my computer for a picture of one of my first cakes, I can't find any! I may have to do some more digging before I find them, hopefully I didn't erase them all!! Anyway, my first cakes didn't sell at all, they were the rolled candle type and i now make the boutique spiral type cakes, which get a much better response! The ladybug cake is one of the recent ones I have made, hope you like it!