Start with a piece of whitish fabric slightly more than 2 sheets of notebook paper (allowing for the seams). I found mine in the remnant bin at the fabric store.
Mark the borders and the vertical red line for each sheet.
Sew a double red line down each piece of paper and "equally spaced" blue lines across both sheets. I embrace the fact that it is homemade, so I didn't want it to be perfect.
With pencil, write your message.
Using the color of your choice, sew your message on the write side of the fabric. I found that using an embroidery hoop made it so much easier.
Fold the fabric in half, right sides together and sew up the edges, leaving a 1-2 inch gap to turn it right-side-out. At this point I'd recommend using a thread color similar to your fabric.
Pass the fabric through this hole.
Sew around the border of the whole sheet being sure to tuck in the part you left unsewn to turn it right-side-out.
Play around with stitch lengths to get the look you want. I used a longer stitch for the red, and a really short stitch for the blue.
I really think it would be fun to make an envelope, but I was so excited to give it to my husband, I gave it to him in a paper envelope.