There is thing thought that being creative is to be without bounds; without constraints.
I have learned, dabbling with visual art that constraints can actually be a good tool towards bringing out your creativity.
To illustrate, consider a blank canvas, or a white paper. You want to draw anything that fancies your mind. I used to get myself into such a situation, and in the end would get quite frustrated with myself. It is when I put myself against challenges (like the Monster A Day challenge) that learned that I can be more creative. I get more subjects to study, more avenues to pursue.
Owing to this realization, I have been putting constraints within which I would work. Consider the field of digital art. It is a sub-category within visual arts, but it definitely cannot be called a niche. So as I worked on it, I though of focusing only on digital paiting and vector illustration. As I was working on different works on those styles (or mediums), certain subjects and underlying techniques seemed to appear.
Some of the subject studies I worked on, grew quite extensive. For example, check out the Dragon Workshop and the Peacock Workshop pages. Considering the subject matter, I have been able to study them in both the styles/mediums of my choice. I know there is quite more I can do, and in pursuit of that, I have realized the underlying principle that would be key to both digital painting and vector illustrations – that is drawing or depiction of forms using lines.
Effectively, by using constraints I have been able to expand to other techniques and styles strategically.
Though I was doing this subconsciously, it was not until recently as I have been discussing these techniques with others, that I realized this.
So, do not think of constraints as hindrance to your creativity. Leverage them effectively and you can use them as a tool to learn more.