Thanks for your advice. That are all points I have to think about (ok that contrast "problem" isnt to think, only to do ^^).

to 2nd: I have no idea what scale that should be maybe I have thought about that first? I can measure some centimeter without a ruler, but everything wider then 2 meters is only "more" (like 1, 2, 3, many, really many!). So I will think about the scale first an then repeat with working on that map. Same problem with the mountains.
But yeah, the ones on the island are really big. but it should be a small island. but how small... i will think about scale

Are there some tutorials about scale? Or pdf's or something like that? Maybe something like "Positioning Names on Maps fromEduard Imhof" <- really interesting ^^