How do you sew side seams of a hat ( when knitting) ????
To sew side seams you should keep the hat, or project facing towards you. Try not to pull the yarn too tight or it will bunch up. A kitchener or a mattress stitch is recommended for side seams.
If you knit it in the round, there will be no seams. If you knit it back and forth, you need to use a mattress stitch to seam the sides--that looks the best. Good luck!