As people, photographers or not, we tend to stick to our comfort zone.... we don't want to step out of it because we're afraid of not being good enough. If we know that where we are is good, we'll stay there as long as we let ourselves... BUT as soon as we realize that we want to grow, we'll be able to muster up the courage to step out of our box.
One of the big steps for me was charging for my photography. I'm so afraid of not being good enough, of having people pay me for something that's not good, but after a while I had to realize that I was letting myself be taken advantage of and I let myself grow. For others, that may be shooting in manual. Personally, I've never used my camera in anything but manual (I was stuck on a point and shoot until just this January, and it was killing me not being able to shoot in manual). For some people, I see how it can be scary, but honestly it's not that hard. I'm still learning about it, but I know enough that I can use it comfortably.
At least once a week, take a step away from yourself. Find that thing you're afraid of trying, and experiment with it... You'll grow and be so happy with yourself!