Mountains are worth spending a lot of time on. They become real attention-grabbers when you add shadows, because the eye is drawn to areas of contrast. So experimenting a lot to find the perfect look for them is good!

The example style is quite close to what I often use, and if I would try to offer some advice, I'd say that your mountainsides are too steep. If you draw them more gently sloping, they'll flow together with the flat land and make it look like the range has risen out of the ground across millions of years (which most probably is what happened!). You can also make the "spine" more jagged, which adds a feeling of size; the more detail you add, the bigger the mountains will look