1. Create an simple icon or graphic in Illustrator

2. Copy the icon and paste it to Photoshop document

3. Select one of the brush tools OR define new brush preset (that you create on your own by hand drawing).

– Edit > Define Brush Preset

4. Create another new layer in Photoshop. Paint the edge and the area of the icon you want to add color effect by using the brush you just saved or you like to use.

5. Go back to the first layer. Select the original icon by using magic wand tool.

6. Go back to the layer where you just painted. Copy the selected area and paste it to the new table).

7.Finally, you can adjust the painted area, as well as the edge of the icon so the icon looks more watercolored.