With kabob skewers, I made a frame for the letter "A" before ever even working with corks. The frame doesn't have to be anything special, just a base to secure the corks to. Once that was finished, I started arranging the corks. It's super simple, you just have to make them fit. Feel free to cut down corks and even cut them in half to secure them better. After the front was finished, I glued two corks to the back of the letter to allow it to free stand.
Here's a look at the finished project...
Happy corking :)