This little annoyance happens to the best of us. Understanding why you are having an artistic blocks helps you understand yourself better. Be it fear of failure or exhaustion, understanding what create the blocks helps us nurture ourselves more than torturing ourselves with self-doubt.
This is what I normally do.
1) Don't wait for inspiration.
I find having space around me works - be it walking in the rain or taking long walks in the park. This will helps me open my eye to new inspiration. The only con I have about walking is that inspiration comes at an inconvenient time. I learnt to bring notes book or pad whenever I go. A quick sketch is a great start of a new project.
Below is the result of doodling in a coffee shop.
2) Looking at the past.
Looking through my past ideas and used them as a platform to create something new. I would build on what I have done before. This will energized me to think what else I can do on a project.
3) Add new skills
I think adding new skills like animation or photography will test my ability. The new skill adds and sharpens my sense of observation and help me understand how my style can evolved. This is another way for me to stretch my style by pushing the boundaries.
4) Take a break
I learn having a bit of distance between work helped to refocus on what is important. Taking a short few hours off, even in a stressful yet important project, clears away old ideas or the one note idea within my mind.
5) Do the opposite.
This is most enjoyable part of artistic blocks. By doing the opposite of "the required" helps with my passive rebellious personality. If you felt that the brief is not giving the freedom to create, try doing the opposite of the requirement. See the result. You might find that you actually "hit" on what the brief is needed more.
6) Cleaning your work space.
This is the least enjoyable assignment. I still find it useful because clearing my work areas. This creates a mental space within my mind. I would scrubbed and cleaned every surface of my work areas.
7) Coffee time
Do a "me time" With me, it is coffee time. Not coffee and typing on my work or coffee with a phone call. The simple joy of enjoying the smell, sipping slowly and tasting the texture of my cuppa helps me relax. Here ideas just poured out.
There is never a right or wrong way of overcoming artistic blocks. Understanding why I am having it. Whatever way I choose to deal with it, I know it will be a more constructive and meaningful way.