I found this out on my own in some sense, but I still have trouble putting it into practice.
I was taking guitar lessons and I would always be afraid to bring in side tunes I had been working on because I thought they were terrible (and they are) but it's tough to give yourself permission to suck when doing nothing hurts a lot less.
I've been playing guitar for 13 years, and I still am not very good.
A breakthrough for me though, was when I stopped obsessing over getting every note right, and instead focused on strumming the right chords. Then, I found playing much more enjoyable, and it was easier to play whole songs and sing.
Once I got that down, I was able to move on to more complex things. Like many things, it helps to embrace your suckage with musical instruments.
Randomly connected, but the game Rocksmith takes this approach. It'll give you points if you get the strumming correct, but are fretting 2/5 notes correctly. There's a huge focus on "get as much as you can right now, but we're going to keep throwing this at you until you get it right."