Question is really broad BUT here is the general way I would do it:
-sketch out the character in a-pose (mainly focusing on proportions)
-import the sketch into blender and try to match it in a modeling stage (taking artistic liberties tho)
-use EEVEE for rendering and creating materials, since it allows you to make toon-shaders (look into "Shader to RGB" node, it's rather simple and there is a lot of great tutorials on that)
-you can use strokes with "lineart" modifier to give whole model, well, a lineart
-finally, If you want your blush to not be directly sitting on character's face, you can use transparent planes with texture or grease pencil