One lesson I wish I had learned sooner is to stop feeling like I have to be absolutely amazing at things to feel happy or content. Somewhere along the line I developed a bad habit of setting standards for myself in life and art and pretty much everything else that were nearly impossible to meet. In setting these standards, I set an unreachable bar for when I could feel content with myself and my accomplishments.
I started doing this at a really early age (like twelve or thirteen) and it has caused me much unhappiness in my life. It has definitely provided a drive, but this brand of perfectionism is a toxic motivator that doesn't offer any sort of reward for when you actually do accomplish something or make progress. I look back at times when I was receiving accolades or praise or any number of things worth celebrating and I remember feeling totally numb because I had this looming sense of how I could have done better.
It's funny because striving for perfection is an absurd goal. For starters, perfection is entirely subjective. For whatever comes after starters, I don't think it exists. When you think of perfection as a goal, it's a mental abstraction of what your future or some product of your future will be like. The thing you initially conceived as being perfect will, in the end, be very different from what you initially conceived. The stupid thing I did was allow myself to be disappointed when things didn't turn out exactly as I had originally conceived them. I could have allowed myself to study and enjoy how my ideas and expectations evolved, but I chose the easier option of labeling things I created as being insufficient or outright failures instead of attempting to understand them.
If I could speak to myself in my mid-to-late-teens-slash-early-twenties I would just be like, "Dude. Relax. Just work hard and try to enjoy yourself and don't think too much about where you'll end up." This isn't to say that I would advise myself to not have goals, I would just say "Those goals will, at best, set you on the right trajectory toward an erratically moving and, essentially, impossible-to-hit target." I've let myself feel the self imposed sting of dissatisfaction when my present doesn't look exactly like how I pictured it looking in the past way too many times, and I can't say that it's ever been a positive thing to inflict on myself.
Be happy with the progress you make. Even if you regress in some ways, there are things to be learned by doing so. Being disappointed in myself for not meeting some impossible and abstract standard has never, ever produced anything except the reluctance to pick myself up again because future me will just be pissed at me for the mistakes I'm inevitably going to make. It's a bad place to live in and I see this miserable self-policing in some form in almost everyone I meet. The only people who ever strike me as satisfied are the ones that give themselves permission to enjoy their present.