Designers work best when inspired. The muse myth externalizes the source of inspiration as something divine and therefore something at the whim of the gods/the universe and thus beyond the control of the individual. This mythic viewpoint also assumes that inspiration is beyond teaching and training. This attitude is just wrong.
Inspiration for designers is the motivation to create. A designer who is feeling uninspired feels both unmotivated and uncreative. Things that are inspirational both motivate us to create and make us think creatively. Inspirational things give us the imagination to see original possibilities and the motivation to realize those ideas.
In low-inspiration situations the systematic designer can fall back on the design process and hope that jump starts inspiration. Just forcing themselves through the process can unlock creativity and create the momentum to motivation. However the design process benefits from inspirational flair, so what if the inspiration block remains?
Focus on fixing the motivation first. Low-energy levels will reduce motivation so fix that by sleeping, eating, going for a walk or waiting for illness to pass. Do whatever it takes to get the brain active again. Deal with any negative emotional issues and distractions. Then focus on the benefits of completing the task at hand. Motivation is about positivity so visualize what completing the task will enable you to do. Complete a goal? Afford a night out with friends? A new toy?
Sparking creativity is about working the imagination. Reboot imagination by playing “what if” scenarios in your head. Think of two seemingly ridiculous ideas together and imagine how they could be related together. Look at images and pick parts of them and think how they could apply to your project. Technically inspiration can be found anywhere, but designers often find inspiration in nature, the surrounding environment (take walk), the fine arts and the work of other great designers. Being around other creative people can help you get into the right modes of thinking.
Inspiration is the mindset of curiosity, imagination and wonder. It is a space where all things are possible and all ideas have great outcomes. Expose yourself to new things, explore your imagination and wonder “what if”. Cultivate these things and inspiration will come.