I have made a few of these adorable glasses sleeves from this awesome tutorial by Sweet Verbena! This is the first sleeve I decided to monogram! I am very happy with the result! Click this LINK for a tutorial. She also has a lot of other great DIY tutorials!
If you do not have an embroidery machine, you can always take your un-sewn pieces to an embroidery shop! If you are interested in purchasing an embroidery machine, check out my blog post!
Even without a monogram, these cases are so cute! & they make a great gift.