Thanks for the replies - I'm going to look into the "Rising up the Mountains" Tutorial - hopefully it helps me. I think you are right on the sharp coastline and I should change it - maybe change the colors or take it away completely. On the topic of rivers - you are absolutely right. This was my first time working with paths and I should try to make them more realistic.

On the topic of scale - I honestly haven't thougth about this. At first I wanted to make a whole continent but the outcome seems more like a medium sized island to me. Is there too much texture? I don't really understand why it looks like an island to me rather than a continent.