Starting with the seasons is the easiest way to ease into themes. Start with winter and use winter things to teach the concepts you want them to learn such as cutting out pairs of mittens and having them match them by colour. You can also put letters, shapes or stickers on mittens to have them match. Find pictures of snowmen and colour them. Have them find some that are alike, or all of the snowmen with stick arms, or wearing touques. Then read seasonal stories or find poems on the internet about mittens, snowmen, etc.

By starting with the seasons you are expanding on what is already familiar to them. This is especially important for toddlers just starting out with curriculum based games. Once you and the kids get comfortable with what you like to do - read, sing, dance, feltboard, colour, craft then you can introduce other themes. The internet is a great resource of ideas once you have chosen your topic.