Draw only with pen, using reference, and keep drawing the same thing until it becomes easier.
Go online and find art that truly inspires you. Collect the art in private folders to look at when you are not inspired to start drawing.
Find human poses, and find the abstract two-dimensional shapes in their figure.
Draw organic volumes. Draw cross-contour lines to describe their volumes.
Find photos of eyes, and draw them. Try to imagine the underlying volumes.
Find something you think looks beautiful - a human, location, object - and draw it carefully from observation.
Look at reference, put it away and draw from memory. Use reference to fix mistakes, and then do it again.
Draw the space *around* an object. Take objects with interesting negative spaces, like chairs and tables.
Draw small design sketches before you spend a lot of time making something.
Draw one-inch rectangles, and try to come up with creative textures to fill them with.
Draw cartoon or comic variations of faces.
Draw poses of animals in motion.