Soon after getting my first 3D printer, I decided to follow this Thingiverse make and make a Splicer mask, as featured in the game Bioshock.
First I printed the various parts. Since my printer was an Ender-3 with 240cm height, I needed to print the mask in separate parts.
After gluing them together, my next step was to figure out how to paint things. From research, going to a model shop, and other places, I learned what I needed to do was sand the model, spray primer on it, and then paint it. It took me a while to get the paint and primer I needed. Thanks to Mark's Models for some help there.
So after gluing the pieces together, I sprayed the primer and sanded. I would later learn the best way would be to start with regular filler for cracks, then alternate between spraying high build primer and sanding with higher and higher grit paper for a smooth look. However, here I was just starting out, so only a coat or two of regular primer and some sanding.
After that it was time to paint. I got white paint from Woodies DIY where they had plenty of sample paint containers. I applied the white paint with a paintbrush. Gold paint from Mark's Models, which I applied with a smaller brush. And voila!