I have studied this when I was learning graphic design, so I will post here a few methods to destroy the creative block. Some are tested by me, some are just theory. (These are for visual artists, but probably you can translate them somehow for other artists)
1. Taking a walk, jogging, any kind of sport. In theory it will increase the blood flow and other stuff that I don't understand but it works for me.
2. Looking at photos, paintings, designs, magazines. This in theory works, although not so much for me.
3. Forcing yourself not to think about your creative issue. The brain will continue to think about the problem in background... Sometimes this is a good idea, but not when you have a tight deadline.
4. Thinking about the target of the art you are about to create.
In general any artwork has a main purpose. Are you trying to explore an emotion? To preserve a memory? To present the beauty of nature? Or the beauty of a human act? Are you trying to create a powerful social statement?
All these type of questions will lead to answers. Answers that will help to create your art.
The next step is to find the actors. In visual arts the actors are lighting, composition, models, location, colors etc.
In graphis design there are lots of rules like balance, contrast etc. There are no rules in fact in graphic design. The "rules" are in fact sources of inspiration.
Hope this helps!
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