a formula for a beenie type hat is:
cast on a multiple of 6 +2 (60+2 say)
(to find out how many you need to cast on, measure your childs head, subtract 1 to 1.5 inches, make a swatch and cast enough stitches to make that number -so if your child head measures 20.25 inches, you'll want to make a 19 inch hat (20.25 minus 1 inch= 19.25, then round down(up to 1/2 inch) to nearest even number)
cast on using needle smaller than gauge swatch (1 size smaller)
make 1 to 4 inches of ribbing.
change to larger needles (the ones you used for swatch)
knit (plain stocking knit or the stitch pattern of your choice(just be sure to swatch in pattern if that is what you want to knit!)
continue till hat is 6 to 8 inches from beginning.(a good measure? measure your childs hand from wrist to tallest finger add 1 more inch (more for turned back cuff) )
IGNORE FIRST AND LAST STITCH (they disappear into seam)
divide remaning stitches into 6 groups (if 60(62) stitches to start, then each group has 10 stitches.
(more stitches to start? more stitches in each group, fewer stitches to start? fewer stitches in each group.)
divide each group by placing marker
ON RIGHT SIDE ROWS ONLY, work a decrease row:
(k1) *Work all stitches in group till 2 remain, K2tog, slip marker, and repeat from *
(if stocking knit, knit all stitches, if working in a pattern work stitches in pattern) end row with (k1)
on wrong side rows, work plain (purl or reverse side of pattern --with no decreases)
Repeat decrease row (right side of work) and no decreae row till 6 (8) stitches remain remove markers, cut yarn leaving long tail.
thread tail yarn through remaining stitches, make a small knot.
then seam hat, (hiding 1 stitch from each edge in seam)