Some excellent photos! I really love the third.
The first photo is very nice, good exposure, but I noticed a bit of flare in it. Whether you like that or not, it's there. If you don't like it, you could always try putting on a lens cap in the future, but shooting into the sun flare is pretty much unavoidable. If there was something that I'd change about the first, I'd put the plant a bit lower in the frame, it seems too centred for my liking, but that's just me. The background is beautiful though, are those the mountains?
The second one's nice as well, good framing, nice scene, but if I were to retake it I'd close my aperture a bit, lower my ISO or throw on a neutral density filter and lower the shutter speed to a few seconds to really blur the water. It looks like you used a shutter speed of 1/25 of a second, I would've gone down to at least 1/3. Gordon did a tutorial on blurring water a while back that you can find on Cameralabs' sister site, DSLR Tips. You can access the tutorial here
The third and fourth are beautiful, very nice composition and the black and white really adds something, but they seem a bit too overexposed for my liking, though. It looks like the second you already had an exposure bias of -1, but some parts still look thrown out. To get around this, you can always use a fill flash and meter on the sky, or make an HDR photo to get most areas properly exposed.
The fifth is also a nice photo, but you may want to adjust the contrast to really get the colours to pop. Otherwise, excellent photo!
Something else that I noticed is that you seem to like to do a fair bit of your shots in the portrait orientation. I like using the camera in its portrait orientation as well, about 60% or more of my everyday shots are taken that way. If you really like shots like that, you may want to consider investing in a battery grip for your DSLR, so that you can have a vertical shutter button as well.
I hope that I helped,