Honestly, I started out with a pattern, but then after I did the first inch of ribbing, I ditched the pattern and made up my own on the fly.

CO 30 stitches

1x1 ribbing for 1 inch

3 rows knit
1 row purl
3 rows knit
1 row 1x1 rib
* repeat 8 row pattern (2 times total)

On last row of pattern, put last 4 stitches on a holder. Turn work and continue pattern for 4 rows, turning at held stitches. On 5th row, knit all the way across, connecting both sides (forms triangle for thumb hole).

Continue in pattern for 4 more rows.

After last row, knit in 1x1 ribbing for 1 inch and bind off.

For thumb hole:

Add the 4 held stitches to dpn. Proceed to pick up 7 stitches along rim of hole (3 on left, one in center, 3 on right). Knit for 3 rows and bind off.

** When making the second mitt, I adjusted the pattern slightly to make the wrist a bit tighter. I cast on 26 stitches, and knit ribbing for 1 inch. Then on each of the next 4 purl rows, I made 1 stitch at the beginning of each row (4 additional stitches total before hitting the thumbhole - 30 stitches total). Continue the rest of pattern as described.