Slip 1, knit 1, pass slipped stitch over, or s1k1 psso, is a simple method that allows you to decrease two stitches into one.
Using this method will create a stitch that leans to the left.
Decreasing stitches is a really useful knitting skill to have, as it will allow you to go beyond making squares and rectangles and start shaping things! Think, armholes for sweaters or the tops of a beanie!
Tips and instructions to s1k1psso:
Slip one stitch onto your opposite needle without knitting it.
Knit the next stitch.
Pull the first, slipped stitch over the stitch you just knit so that now there is only one stitch left.