Most of the customs I do involve a lot of sculpting. It takes a lot of time. Action figure customisers do use recipes though. If one customiser finds a good way to make a figure, then they can share it with others. I used this approach with one of my quick customs below.
As I said, I do a lot of sculpting, but these customs use really minimal sculpting. They just use body parts from different figures that once assembled together, make a new figure.
I've also made a light tent. I was disappointed with the photos I was able to get of Jem. She was made in the darkest months, and I was really annoyed that I couldn't capture her 80's colours well in photos because of the lack of decent daylight accompanied by good weather for taking my photos outdoors.
I got a cardboard box, cut holes in the side and covered them in a white bed sheet. This helps diffuse any light any thus, not create shadows. I've just got a coupla crappy bulbs from a coupla desk lamps so the light isn't so great, but I've found out how to balance the colour of those bulbs so that the camera reads it as white. The difference in the photos I can take is amazing. I'm still perfecting it, but I'm getting there!
Anyway, here's my customs of Iron Man and the Red Skull: