Have you had them sort by "sticks" and "circles"? You could create a t-chart and they can tally the number of letters that have sticks and the number with circles. Or, you could give them a venn diagram and have them cut and paste (or manipulate) the letters that only have sticks, only have circles, and have both.
Here's an older post about sorting
I actually was thinking of rewriting the post with pictures. I like the idea that Dawn shared about the t-charts and venn diagrams for recording.
Good idea to have pull out one particular letter (several Es). I also like letting them pick the category for sorting (after they become better at sorting)! thanks!
My 6 year old and I just did a sort with letters. I just posted about it today.
Becky, these ideas are great. Love the one about lifting up your pencil when writing it/not. Thanks for sharing the link.