The photo reference below is of some artificial tulips that I use to decorate with each spring:
It is very important to use just enough water to get the paint to the sponge. The puddle of color should be mostly pigment. It will have a consistency of heavy cream. If you use too much water and the sponge gets too wet, the color will leak under the stencil and the edges will not be crisp and sharp:
Once everything is dry, go back and fix any edges that may not be to your liking and then add your header or text. Consider using a coordinating color like a darker green or pink rather than black.
Last go back and strengthen the outlines around the tulips to give them more energy:
I hope you can join me at Keeton's down in Bradenton for the class on Saturday, April 25 and we'll paint tulips together!