Use a wet palette or keep paints slightly moist
Apply a base layer of paint
Work quickly before the paint dries
Place the second color next to the first color
Use a clean, slightly damp brush to soften the edge between colors
Use small circular or back-and-forth brush strokes
Add thin layers instead of thick layers
Mix colors on the palette before applying for smoother blending
Use glazing medium to extend drying time
Mist the surface lightly with water if needed
Blend while the paint is still wet
Feather the edges with a dry brush
Layer multiple thin coats to build gradual transitions
Clean the brush between colors to avoid muddy results