Knitted clothing: What should you keep in mind?

Dear users, dear authors,
If you want to knit clothing, what should you keep in mind?

First, the needle size and yarn should be a good match.
Whether the specified needle size is appropriate or if you should use a needle half a size or a full size smaller or larger depends on the knitting technique.

Next, choose the yarn based on the project.
Lace knitting tends not to work well with thick yarn.
Cables, on the other hand, work well with rustic yarn.
Knit-purl patterns are most visible in solid-colored, smooth yarn. For this, the yarn should be suitable for at least needle size 3.

Thanks for the info.
What is rustic yarn?

Rustic yarn is usually made of virgin wool or a wool blend and is typically knitted with size 4 needles or larger.

OK, thanks for the info.
But this rustic yarn isn’t really suitable for summer, is it?
Can you felt it?

That’s right—it would be too warm for summer.

For felting, the yarn must be made of 100% virgin wool.

Can you only use virgin wool, not cotton?