I really like Bev's The Mitts
. They're really basic and knit flat and easily modified for fair isle, cables, whatever. Also, to size up just go in fours: CO 4 extra sts, k 4 extra rows (I put the extra rows in right after the ribbing. If you wanted to size down, I would either change needle size or just minus 4 for the cast on and minus 4 rows in hand length.