As I was looking around for some tips on hot wire foam cutting and shaping I ran across the site of The Kamloopian. His actual name is Steve Delaney and he is a mixed media artist among many other things. What caught my immediate interest were his videos on terrain building which can be accessed from his main site through the video link. That takes you to his YouTube Channel which houses 350+ tutorials on many different aspects of terrain building from simple hills to architectural structures. He works in many different scales and it is all very applicable to gaming or model railroading hobbies. He's got an easygoing style and although, as he readily admits, the naming of his videos could be a bit more consistent, using the search feature in the uploads section in the grid view (linked above) should help a viewer glean whatever they need from his stockpile. He tries very hard to be quite complete with close ups when possible and has additional pictures on the main website for better views when necessary. Check him out when you have the time and definitely bookmark this treasure of a website.