Take a gander at this video if you are interested in a simple way for crafting irregular, craggy hills, complete with built-in platforms for miniatures to stand upon. I think he overdoes the dry-brushing, but his construction method is quite good. I really like how he integrates platforms for mini's to stand upon.
I especially like the fact that these 'hills'/'mountains' are completely customizable, not only in size and shape, but also in colors. They can be painted up to suit any genre. I can even envision making asteroids using this technique, mounting them upon a stick to elevate them above the tabletop, for space ship games.
They can be used to create islands in an ocean, for ship-based games. Need an island really big? Make it. Need an island really long? Build it to the size you need!
There are sooo many variations on crafting hills… This one struck me as valid, useful, and it produces decent results. Therefore, I chose to share it here.
One of the great qualities of this technique, is that it is universal in scale. For example, I can build hills using his techniques, for 10mm figures, or 54mm Army Men figures. I game with 54mm Army Men figures, mounted on 50mm bases. To be able to employ craggy hills and cliffs for my Army Men games, is something I truly appreciate. Here's to hoping others will find these techniques useful as well. Cheers!