Another easy and fun way to work on letter recognition is to print off a large block version of the letter you are wanting to work on and give them a bottle of glue and some sequins, or buttons, or pom poms, or whatever you would like. They glue the objects on the letter! Easy peasy. Don't forget to talk to them about things that start with the letter while they glue.
Here is a website with printable letters you can use: