February can be an easy month to create your preschool lesson plans... Unless you have families in your classroom that don't celebrate Valentine's Day. If that is the case then you have to be more creative.
Some easy preschool themes for February could be Friendship, Post Office, and at the end of February, a Dr Seuss theme(March 2 is his birthday).
Some ideas for Friendship could be Friend painting(having them at the easel together painting together), have them make a gift for a friend, and you could even have a "Friendship" party in lieu of a Valentine's party. You could exchange "Friendship" cards they make in the writing center, or pre-bought ones. You could make "Friendship cookies" as a cooking activity for the party (use a gingerbread cookie cutter and make 2 cookies hold hands). In doing these activities, you are teaching the value of friendship, cooperation and patience.
With the post office idea you can plan a trip to the post office to see how the mail gets where it needs to go,(be sure to mail something back to the kids). Something else would be to set up a post office center in your classroom with a mail slot for each child(this is easily done with shoe boxes). And when the kids go to writing they can "write" notes to each other. Be sure your writing center is set up with stickers that resemble stamps and mailing labels, envelopes, and ink stamps too. This works well with the friendship theme preceding the post office theme.
And finally with the Dr. Seuss theme. Just have a Green Eggs and Ham day with a cooking activity, have a Red Fish Blue Fish day with a fish matching activity, and so on with your favorite Dr. Seuss books. Have a birthday party for Dr. Seuss, make Cat in the Hat hats, and of course read the books!
I find that if they know more about the authors, they become more interested in literature.