Actually I used "Not so random coast line" tut by RobA. This lead me to:
Next I applied the "Using GIMP to Create an Artistic Regional RPG Map" tut, where I got the idea on how to add sea level.
Even if I didn't use exactly the same way, the result have been sufficient for me:
In various tutorials, there have been pointers to the pattern usage, unknown to me till this tryouts:
Oh yes, the mountains. Very mysterious area full of "Bumps" and "Embosses", multilayers, etc.
Here I read so much threads, that I cannot say which influence have been the most usefull.
Maybe the authors will see their techniques :-).
Forest added using the pattern style: