Blending can make marker artwork look softer, richer, and more dimensional. The key is to work gradually instead of trying to create a perfect transition in one step.
Begin with the lighter color and apply it to a larger area. While the ink or paint is still workable, add the darker color near the edge or shadow area. Then use the lighter marker again to soften the transition between the two colors.
Choose colors that are close to each other, such as yellow and orange, blue and purple, or pink and red. These combinations are usually easier to blend than strongly contrasting colors.
For acrylic markers, allow the first layer to dry if you want clear, separate colors. If you want a softer transition, blend carefully while the paint is still slightly wet. Always test your colors on scrap paper before working on the final piece.
Blending takes practice, so do not worry if the first result is not perfect. Experiment with pressure, layering, and color combinations until you find the effect you like.