The easiest advice I can give making mountains.

The nicest shaped moutains can be made the following way......

SHAPE:
Choose 'Ridged Multifractal' from the pulldown list next to the button that says 'Fractal' in the Editing Tools window.
Then use 'Gaussian Edges' and 'Raise/Lower' in combination making sure not to raise too high (or you'll get a flat mountain top).

**MATs:
**Choose any of the Terrain MATs and altar to taste in the Deep Texture Editor (There are plenty of tutorials for this subject in the Tutorials section)

**CONCLUSION:
**Experiment a lot, it won't come overnight. Good luck.