The first time I tried on my Ergo I cried (I was sleep deprived mind you :P) because it didn't feel right! It took a couple of goes at getting the adjustments right and now I LOVE it! I found if the straps that go under my arms are too tight it puts more strain on my waist. Where Ange described around your waist is spot on!

Give it a few more goes, I'm sure you will love it eventually!