I think you may need to start folding sooner in hands where you think you are behind. Study some of your medium sized losses and see if you can find a better spot to fold than the one you found (or didn't find) and make sure you know why it's a better spot.

Look over your big hands that aren't getting paid. Sometimes your opponent just doesn't have a hand to pay you off, but sometimes you are either playing them too fast (trying to get it all in asap) or slowplaying too much and therefore not building pots early enough in the hand. Try to find different lines that you can use to extract more from your opps probable range.

Remember, putting opponents on ranges isn't just a tool to save us money and allow us to fold, it is also a great way to maximize our profits when we are ahead. If we can narrow their hand down to a few possible holdings we can find better bet sizes, and make as much as possible off of them.