The real key in mountains is going down them. Downshift and use engine braking, and if you need to supplement with brakes do so in intervals and don't ride them continuously or they'll overhead and won't work very well.
Going up hills will be slow at times. Use the right lane if there is one, and use pull-outs to let others pass periodically if you're on a narrow mountain road. People get agitated following a slow RV going 25 MPH up a long grade when they don't utilize pullouts, and that often prompts some stupid decisions in terms of trying to pass where it isn't safe.