Edges: always do a single turning chain as last stitch of row regardless of pattern you’re following . Check carefully you have really reached the edge.
Unless you are working from one side only, just going round, there’s no difference as you work each side separately turning it over each time.

Practice…… just keep on keepin on……. You’ll get the hang of it. And you can always rip up your practice pieces and reuse the yarn if you really hate whatever you’ve made. Or turn it into a pet blanket perhaps???

………. If you’d like to sign too check out 38 Degrees !!

Not something I pay much heed to …. I’ve crocheted dozens of blankets of all shapes and sizes. If the yarn is too thin I’ll double it up, but it all works out in the end.
Recently I’ve been making lap/ yoga rugs out of assorted leftover yarns. They’re very popular & a cheap way of finding material.