Glad to hear you picked up photography. What camera are you using?
#1 has great composition, I really like whats going on in the background in this photo. Only thing I would do is most definitely bump up the exposure and that will help this shot a lot.
#2 This photo has amazing colors but doesn't have any real subject for the viewer to focus on. All I really see is just a wall of brush nothing really interesting.
#3 Everything in this photo is out of focus and underexposed. Use a higher Fstop to get that whole range of detail out of the landscape, I would also recommend using a tripod to help supress that camera shake. One last thing go out on a clear sky, A nice pretty sky really makes or breaks the whole landscape. The whole photo could be in perfect focus and looks nice, but if the sky is just a sheet of grey it really makes the photo "bla".