Filter Opinions About Your Work

 Beware the unsolicited opinion of your creative endeavors, but more importantly, don't ask people what they think.  The wrong people anyway, and that would be anyone who doesn't completely understand your medium from direct experience.

If you're in a classroom experience that would be different, it's the job of the teacher to critique and help you learn more about your chosen medium, as long as it's constructive and helpful.
I'm old enough to have had many classroom experiences, not all of them good however.  Teachers are just people too, so choose them wisely.

When I'm working on a piece I try not to open my energy to someone else's ideas unless I'm really stuck.  But even then I move forward with what I think it needs or where the inspiration leads me. 
I don't create to sell specifically, and I don't always stick to a style.  I'm a bit of a rebel when it comes to my creativity and I'm going to do what pleases me - even if it doesn't sell.  That's the hard truth that can come long after you've toiled and churned out piece after piece.

I kind of gave up black and white fine art photography for that very reason.  It sort of fell out of popularity for a long time and meanwhile a lot of really good photographers came along and made stunning images, making my simple images look, well, simple.

The important thing to remember about creativity, about any medium when finished, is that it is all art, and art is subjective, always.  That's the freedom and the challenge.
The best news however is that there is no end to what you can create!