My advice would be to read all the books out there in your genre, write, re-write, research, and never give up. (I've had years of opportunities to read children's books, since I'm a mother of two - ages 14 and 8 - and I've gone to the library every week from the time they were babies.) Then, if you get tired of submitting your hard work to the big publishers and getting rejected, go the indie route. I was lucky to come across a local indie publisher, who does the cover/page design, ISBN application, and uploading. We worked through Amazon's Create Space, and it was a relatively simple experience. The only drawback to this was that it is print-on-demand, and I was unaware that book stores cannot stock this type of book. They can, however, special order them for customers, or readers can order from Amazon or B&N sites.