I started with one of the basic mitten patterns from Homespun Handknit and just kind of did them. If you've never made mittens before this may not be a pattern for you.
Gauge 6 stitches/inch. I used size 4 needles, I think.
1 skein Lamb's Pride worsted. Don't worry about the extra twist in the yarn, the vertical stripes in mittens are pretty cool. Mine are eggplant purple.
Basic plan for women's med or man's small (my size <G>):
Cast on 44 stitches over 2 needles join and work in K2, P2 ribbing
for 3.5 inches
Switch to St stitch for 0.5 to 1 inch
Increase for thumb - looks like I did 6 increases total, spaced every other round
Rnd 1: k1, knit into front and back of next stitch, knit to last 2 stitches of round, knit into front and back of stitch, k1
Rnd 2 and all even rnds: knit around
Rnd 3: k2, increase, knit to last 3 stitches, increase, k2
Rnd 5: k3, increase, knit to last 4 stitches, increase, k3
Rnd 7: k4, increase, knit to last 5 stitches, increase, k4
Rnd 9: k5, increase, knit to last 6 stitches, increase, k5
Rnd 11: k6, increase, knit to last 5 stitches, increase, k6
Rnd 12: knit and then place stitches between increases (total of 14) on a piece of waste yarn.
Cast on 4 stitches across thumb gusset and continue in St. Stitch for 3 more inches.
Decrease 9 stitches evenly around next round.
K 3 rounds
Decrease 9 stitches
K 3 rounds
Decrease 9 stitches
K 2 rounds I think there should be one more decrease in here, but the mittens have fuzzed enough that I can't really tell.
When they look like mittens, run the tail through the remaining stitches and weave in the end. I decreased too many times, and the tips of mine are a little pointy.
Thumb: Transfer stitches to needles, pick up 4-6 stitches across gap knit a few rounds and start to decrease. The thumbs of mine are really fuzzy, and I can't even tell how many stitches I started with, let alone how the decreases went. It looks like I did 3 evenly spaced decreases.