start with a different medium you're used to. If you're used to sketching on paper first try 3D rendering or clay modeling. I look at design blogs for inspiration, usually save the pictures of designs that intrigues me onto my hard drive and browse through them once in awhile. Look at nature stuff, small microbacteria size things, deep under water creatures, repeating patterns. Go back to basics and practice piercing, cradling, wedging, dominant, subordinate exercises.