Okey, here is a guide that will show you, how you can create nice looking mountains with triangle-method.

1 Make your mountains
Now the mountains look good, but they are flat at the top
So, we will make the top part of the mountains to look like this

2 For this method we are going to use the triangle-method. First create a brush and cut it on 16 small triangles.
After that selects all 16 triangles and selects vertex tool (shift+v) and try to make those triangles like peaks

3 When you are don with the peaks, you must put them on the mountains.
Now this looks weird, so we need to fix it. Selects the peaks and the vertex tool. With the vertex tool select these points you need to fix by holding ctrl.
Until you don't receive something like this.

4 Now there is one last thing we need to do copy those mountains and scale them to 3/4/5 for X and Y axis, put some cool jumps, some nice atmosphere and submit at XJ

5 This is what I made with these mountains.

For a better understanding of your tutorials please use for your pictures the following BBCode [ img ] source link .jpg [ / img ] (without spaces).

I've edited your post but please, in future, modify or post the bbcode I've told you, thanks.

Certainly, it's better that way.