When modelling the 3rd ghost for the animation short I begin with a cube which I then added a subdivide modifier.  With the modifier on I started to model the ghost shape without applying the modifier so I could control the amount of polys I ended up with. I only added the modifier when I was happy with how the model looked.

Once I had my model completed, I started fixing the UV’s. I added a checkered texture and set the coordinates to UV so I could easily see how the UV’s looked. I careful marked out each seam and unwrapped the UVs until I got the UVs how I wanted them.

When the UV’s were fully completed I exported them out into substance painter.

(I later went back and changed the roughness so the model wasn’t as shinny).