oh yay! being able to understand how to fix a stitch a few rows down is definitely a necessary skill! i find that using a crochet hook is the best way to knit/purl a stitch upward.

i can usually kinda tell where i've made a mistake - but that's after carefully looking over what i've done. in lace, i have a much harder time telling where i went wrong and i definitely cannot even try to do any laddering!! so what i do is count each pattern row once i've knitted it, so i can make sure i have the correct amount of stitches (and boy, have i benefited from others who usually have already figured this stuff out and share their charts with the counts on them!)

i just had to figure out where i created an additional stitch on this last row of the shawl i'm working on and it took me quite a while after carefully reviewing what i had done. but i prefer that to having to frog back. it would be a disaster for me especially since i don't have a lifeline inserted.