I’ll let others chime in on portraits and whatnot…I’ll focus on the landscapes:
There’s a lack of foreground interest with the two landscape shots. While I’m sure the view was great and worthy of the share, they don’t necessarily make me want to be there. A strong composition would include something drawing the viewers eyes through the image.
http://www.flickr.com/photos/105757377@N06/10331762255/in/set-72157636662169603 – this shot appears to be a little too blue (but I’m also viewing on an uncalibrated monitor while at work) in the left 2/3’s. The clouds in the upper third have a purplish color cast as well. The overall feel of the image is slightly unsettling, but that might be the angle of the water vs. the mountain ridge – I can’t tell which one needs to be leveled.
http://www.flickr.com/photos/105757377@N06/10331721826/in/set-72157636661220483 – Is your subject the skyline, the trees, or the lake/pond? It looks like you stopped on the side of a walking path and took this shot because it ‘looked nice’ with the trees framing the pond. The sky is bland – this is half the pain of being a landscape photographer. You don’t have the option of choosing when the sky will cooperate with you, so you have to come back another time. There’s also a strong right tilt in most of the buildings.
http://www.flickr.com/photos/105757377@N06/10331790305/in/set-72157636661220483 – now w’re getting somewhere… except the bottom part of the image for the viewer to walk through is cut off. The right wall is also higher than the left, creating a bit of a disproportion in the image. Make sure the horizons are level – the arch and the wire in the upper third are tilted left.
Keep working at it. Read a lot and shoot a lot.