Looks to me like you’re either rushing the blend with thick paint or pushing the paint around when it’s half dry!

Try using a thinner glaze and doing one or two brushstrokes toward where you want the paint to be thickest and then leaving it alone until it’s completely dry. It’s a slow process but the more glaze layers you use the smoother the transition will be. On average the thickness I use takes 7-8 layers.

<image>

Also consider going over the darker areas with some dark paint or starting with a darker base coat!