Find a good lightsource

Make a new layer and choose a colour for ur shading (I chose a magenta purple cuz it looked nice on her) And set the mode to shade if u got sai.

Use the bucket tool, set that layer to clipping group and use the eraser, make it soft and erase parts that shows where the light comes from.

Refine it, touch it up and then make a new layer, use the bucket and fill everything orange and set the mode to shade, set the opacity lower, this way the colours looks more warm.

Oh! Uhmmmmmmmmmmm..... Im not rly that good at explaining.I think that's it for how I shaded this, sorry if its a mess to read but thank you for the kind comment!