This has been a thorn in my side for quite sometime. And lately I have been making lots of potholders - so the problem has multiplied itself by many times. Yikes! And then, lo and behold, a light went on just as I was rounding the corner of a potholder having just finished one side. The easy side. It already had a base of single crochet tops that I could easily use. Then WHAM. That moment that one realizes just what you should have known for years.
When you crochet around a side that has the crochet loops all in order you are just putting your hook vertically into the loop below through the loop above it! Amazing!
So after I got around the corner, I raised the hook in an actual vertical position and used my thumb to measure just how low I had to go into the fabric the first time. I then just inserted the hook exactly below that loop ... and drew up the loop from that measured spot. Then the next area was "spotted" the same way so that I did not go further or less into the fabric than before. WOW! What a difference it made ... Maybe not yet PERFECT but I can say that it was darn close.
Next time you want to edge something try my 'trick' and see if it helps you! To start the process, be sure to put your hook in the vertical position - straight up and down - and let the top loop be your guide.