These are standard abbreviations that I use in my patterns.
st/inch – stitches per inch
rpi — rows per inch or rounds per inch, depending on the piece is knit flat or in the round respectively
s1 – slip one purlwise unless specified otherwise
yo – yarn over
k – knit
p – purl
k2tog – knit two stitches together
ssk – slip the next two stitches knitwise, then knit them together
dec – decrease specified number of stitches in manner of choosing.
skpsso — slip one, knit one, pass slipped stitch over
k3tog – knit 3 stitches together
sk2togpsso – slip one stitch, knit next two stitches together, pass slipped stitch over
m1r – insert right needle into loop one stitch below next stitch, and knit as normal.
m1l – insert left needle into loop two stitches below last stitch, and knit through back of loop.
kfb – knit in front of stitch, and then knit in back of the same stitch
As more are used, they will be added to this page. If you have a question about an abbreviation that you cannot find on this page, please contact me.