What acrylic blending techniques and mediums yield smooth skin tones and skies?

[Riley.L]

I'm relatively new to acrylics and I'm struggling with blending; the paint dries so quickly that my attempts to create smooth gradients, especially in skin tones or skies, end up looking streaky and patchy. I've tried using retarders and working wet-on-wet, but I haven't found a reliable method. For painters who work primarily with acrylics, what specific techniques or medium combinations do you use for successful blending, and how do you manage your working time and layering to achieve a more seamless look?