LordHelmut:
Im not being mean or anything, just dont want to pump you full of lies and you make it really far with a crappy tileset. Its not that great, try going for an original tree rather than just drawing lines and stuff on the previous one. The bush as well as the tree have to much black on them, try outlining in dark green rather than black.
*edit*
http://www.pixel-zone.net/tpz/tutminirocks.asp
theres the link. Pixel Zone is a place where artist go. I must ask that you dont go there and beg them to join your little projects because frankly, its retarted. These people do art because its fun, not to have power on some little Graal server which is actually no power at all. Anyways, this is a good site, just dont screw around with graal topics there.