I used the Crochet Fingerless Gloves pattern as a size guide and used an Afghan/Tunisian Knit Stitch. This is my new favorite crochet stitch. It looks like knitting and it's very thick.
I used a double crochet foundation stitch which makes a nice edging at the bottom edge.
Here is how I adjusted the Crochet Fingerless Gloves/Mittens pattern for the Afghan/Tunisian Stitch:
22 double foundationless stitches
Crochet 24 afghan knit stitches
Make 34 rows. Don't cut the yarn. You will continue to sew the seam.
Count 17 rows from the bottom up and put a marker.
Skip 5 rows and put another marker.
Fold the right sides together.
Use a slip stitch to sew the side seam to the first marker.
Slip stitch in one edge for 5 stitches.
Aligning the next two markers, continue the slip stitch seam.
Thumb: Use DC to pick up stitches around the thumb.
Crochet two or three rows depending on how much you want to cover the thumb.
Yarn: Lion Brand, Vanna's Choice, Color 400, Oatmeal