The domain name doesn't matter much from a SEO point of view. You don't have to make subdomains for your site to rank better. It will do just okay without it. Making categories (folders) can help -- I wouldn't go for "to-learn", "to-sing" or "to-whatever". I'd go with "learning", "singing" and such. In short, I would avoid using dashes in category (folder) names.
Naming your pages' URL's should be in the manner you described. If the title of your page is "Give your child a gift", you should name your page "give-your-child-a-gift.EXT" (EXT = .html, .php or whatever).
To make a long story short, your URL should look like this: "http://www.motivatechildren.com/learning/give-your-child-a-gift.EXT".
My 2 cents.
