Not sure I have anything to share or how to exercise for poetry creation. Just let the words flow. Allow yourself to write basically and not logically. Poetry, for me, is about emotion not sense. If I want to write sensibly than I would write stories. Full and complete sentences – direct meaning.
Poetry or prose is free form. Yes, even within any style used. Rarely does poetry spring forth without needing polishing. Go further into your creative mind. The area that’s way away from the writing rules.
Pumping this well for, say, sketching, drawing, painting, heck even sculpting, that’s fairly easy. Play. Take medium you’re planning on using and play with it. Feel the clay or stone or plaster in your hands. Squish the clay. Look at it. Trace your fingers along its sides. The texture of the material. Mix the paints. Combine them. Paint a rainbow to see how they look together. Test their shades.
Drawing? Draw simple items. Just draw them with easy lines. Practice with easy lines. Which way is the light falling on the object? How long would its shadow be? Draw boxes. What does it look like inside or the outside? The depth and angles.
Give yourself permission to play. Test. Remember this isn’t the final product. The end aim. All mistakes are allowed and wanted.
Also remember sometimes the magic is released through the mistakes.