Actually I used "Not so random coast line" tut by RobA. This lead me to:

xTrain02 land.jpg

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:

xTrain03 sea added.jpg

In various tutorials, there have been pointers to the pattern usage, unknown to me till this tryouts:

xTrain04 grass land.jpg

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 :-).

xTrain05 mountain.jpg

Forest added using the pattern style:

xTrain06 forest.jpg