I have to second the Stitch & Bitch book. I already knew how to knit but aside from that it explains so much I’d never learned or considered before in the most clear-cut way. (What a purl stitch looks like as opposed to a knit stitch, how to modify a pattern, how to READ a pattern to begin with, etc.) It makes it seem like things are fun and no big deal and encourages experimentation.
For example when I was relearning how to knit I just grabbed some yarn I liked and started working with it. My husband said “what are you knitting?” and I said “I don’t know yet.” (I made it into a hat, after the fact, heh.)
Also for anything complicated, like a cable or anything just think: test swatch. It takes maybe 30 minutes/an hour but will save days of frustration.