Ok for mountains you need to establish how big it is and what type it is.
If the mountains are realllllllly far away make them small but too much detail.
If the mountains are realllllllly close up make them big but with lots of detail.
For detail, look at pics of mountains from tinternet.
For the type of mountains, thats easy, your ovbs going for rocky mountains. Mountains are rocky, so there made of rocks, so establish where one rock ends, and one begins.
Find your own styles of mountains too, this helps to estblish your own track, which you have not copied.




