Yes, practice practice practice.
That's probably the most frustrating part for me too. The style I'm ultimately heading for (and my thoughts on this change daily!) is I think something between Ascension's latest and the one you posted from Torstan. I keep wobbling back and forth, and I know what will happen is that eventually I'll end up with something that's in the same ballpark but still uniquely me.

If it helps any, my progression since starting mapping (for hand drawn look anyhow) is kind of like this:
Followed tutorials almost to the letter, and used copy/paste from already existing maps to get mountains, trees, and symbols.
Used other people's mountain and symbol brush packs
drew out my own mountains and turned them into brushes to use them, my style but still easier than drawing out by hand
Incorporated Fluesopp/Ramah's forest generator
Realized that the best way to make something look hand drawn is to draw out the whole thing
Got frustrated with very slowly progressing map since I'm drawing everything from scratch
Got extremely pleased with hand-drawn results and forced myself to keep doing it no matter how frustrating it is



Ascension's point about drawing at double size and shrinking the final piece does go a LONG way to turning those differences into a personalized look/style. Give it a shot, you'll be nicely surprised by the results.