It's very freeing to play around with different painting techniques before you lay paint onto a final project. I tried what are called subtractive techniques and here's how they look.
Plain water spattered onto a wet wash and lightly dabbed with paper towel to lift color. Looks like bubbles or could even be snow.
This one uses the same technique as above only I dropped alcohol ink into the wet paint. The citrus looks rather heinous but the technique is very useful for making rings or bubbles which is excellent for mermaid backgrounds. I think I'll try a different color or use the blending solution next time.
This one is a two color wash. Lay a wash of one color over another and press wrinkled plastic wrap into it to reveal color underneath. I used wax paper which also had the desired effect.
The last one is part of the same background as above only you can see where wet paint was allowed to drizzle into wet paint. I also used the end of a paint brush to draw in some shapes. These were quite fun to try and very helpful in determining which techniques might be best for my mermaid project.