Very nice work. I really like the first two, however what I didn't like about the third one was that the trees are too horizontal and the background on the right side is very plain and... well, it's barely a background terrain at all! I recommend adding one.
The Fourth one was very plain too. What made this one feel so empty was the empty patch in the bottom of the terrain where the rock tiles are. Replace that with environmental doodads or something to better help the atmosphere.
I didn't like the fifth, sixth, and seventh terrains though because of the very pointy mountain in the island. Try to make mountains look more smooth and bumpy, instead of rocky spikes poking out of the earth.
Overall though, you're pretty good. I think that if you keep at it, you'll eventually be a very good terrainer. I believe this because your first three terrains are more than decent, which is suprising! So good job again and I hope you show us more of your work in the future.
PS: Never rush your terrains! No matter how bad we want to see your terrains, it is best to let us all wait and take your time to make your terrain the best it can be. Rushed terrains always come out looking horrible or not as great as they could be, plus it is very noticable.
~
Craka_J