Both these techniques are quite simple to do, and the results can be startling!
Technique #1: Soak good watercolor paper in clean water, place it on a hard surface, and apply plenty of vivid, strong liquid watercolors. Lay absorbent textured materials into it. Examples include crocheted fabric, swirls of string, or open-weave burlap. Add more full-strength paint as desired. Place a sheet of glass on top and let dry overnight. If necessary, add a book on top of the glass to weigh down your creative sandwich!
Technique #2: Buy cheap colored tissue (the non-colorfast kind!) in strong colors, tear pieces as desired, and arrange them on damp, smooth watercolor paper. Spray with more water as needed. Then cover with the sheet of glass as before and let dry overnight.
Experiment with both these methods and do try variations, too! Much luck to you.
(I'll publish your successful attempts at either of these here, with you credited, of course, if you wish to send me good quality images.)