This video shows a neat build of a ruined tower terrain piece for your wargames table. It would work well for all sorts of genres and periods.
modeling
Making A Stone Barn
Barking Irons has a photo tutorial on making a stone barn for 28mm figures.
Making “Vertical” Hills From Wood Chips
Maiwand Day has a nice photo essay on making a wargames mountain with a vertical profile. It’s really great looking, and is on my list of future projects
Modeling Spider Webs
Massive Voodoo has an interesting tutorial on modeling realistic spider webs. It makes me think of Mirkwood.
WWI Bombed Out Copse
Roundwood’s World has some great photos of his WWI wooded terrain board.