Here’s a tutorial on scratch build a void shield generator. While intended for Warhammer 40K, a model like this could be used in a lot of science fiction games.
Modeling
Modeling Giant Science Fiction Crystals
Here’s a video tutorial on modeling giant science fiction crystals. The intent is making large, emerald style crystals for Necron terrain, but I can see these in any number of settings, including pulp action lost worlds.
Making Counters For Games
The League of Ordinary Gamers has a tutorial on making counters for your games.
Making Bayou Swamp Terrain
Here’s some good viewing on making Bayou swamp terrain.
Modeling Shrubs
The Mordheim in Montana blog has an illustrated article on making bushes and shrubs for your 25mm wargames.