Well, the first thing you need to figure out is the scale of the map you want to make. There is galaxy map, solar system map, world/planet map, continent map, country/nation map, regional map, city map, building map, dungeon map, and ship map (starship or sailing ship), etc. Once you know that then you can look in the tutorials for the appropriate scale if you like. Sometimes the style you want to do is not exactly represented so you have to make things up as you go. There are as many styles, or more, as there are scales. The best thing is to go through a few different tuts just to learn the techniques and once you feel like you have the techniques down then start adapting them to where you want to go.