[COLOR=Purple][SIZE=3][FONT=Comic Sans MS]:waving: I think, personally, it's a good idea to make some mistakes on a practice piece and then practice fixing them. Drop a stitch and learn how to pick it back up and knit up the column with a crochet hook.
Practice tinking or knitting back several sts and then learn what twisted sts look like. They aren't a problem cuz you can just knit twisted sts through the back loop and that fixes them.
Examine your knitting so you know what it looks like when it's done correctly so you can identify and fix mistakes. It really is a good skill to have when you find a mistake 8 inches below where you are now. Fixing takes less time to do than ripping it all back and "starting over."