Have you noticed that your gauge tightens up when you knit in the round? If so, join the club! It’s very common for the knit st to be tighter than the purl st so when you eliminate the purl rows by knitting in the round you often tighten up significantly.
In most of my sweaters you will only have two short seams on each shoulder; the top, bound-off edge of the front to the sloped back shoulder and the top, bound-off edge of the sleeve to the side of the front. Since there are only two little seams it’s worthwhile getting them right.
I often knit yarn on a larger needle than suggested because I like open, drapey fabric. When you do this, be careful when you measure your knitting.
I am often asked about yarn substitutions and I always encourage them. Choosing a yarn in a color and texture you love is what makes a garment unique to you.
I like long tail cast on. I like the neat edge of what would be considered the “purl” side. But how often have you CO 200 of 220 and run out of yarn, ripped, CO again only to have 3 yards of extra tail at the end?