I apologize, I did not see the link to your Flickr. The biggest problem I see with these ( and not all of them, there are some good shots there ) is composition. Just a few examples:
The Marlboro shot -The cigarette butt is such a small piece of that shot and almost unrecognizable.
The Audio Mixer - I don't think the subject is recognizable enough the way it is shot. And if you are going for abstract, I don't feel its abstract enough, its sort of somewhere in limbo. It would have been better to possibly get some of the lettering on the board (PAN, EQ, etc ) by shooting at a different angle, and possibly some of the faders in the shot. Even if they were slightly OOF while the pegs were sharpest, I think it would have worked better.
The kitten crawling between grass and rock - The shot could use a little less space at the top of the shot.
The two kittens on the chair - The human legs in the background ruin it, but aside from that, had you shot from a lower perspective so that you were eye level with the kats, and a little tighter, I think the shapes of the chair and the kittens would have worked much better.
The Rooftop Graffiti - Nothing says "rooftop" about this shot aside from your title. If you need a title to dictate to a viewer what they are looking at, that should be an indicator right away that either the description you wish to convey isn't that important to the shot, or you failed to compose the shot in a matter that told that story. Much tighter shot on the graffiti and concrete wall would have been much cleaner and more effective IMO.
To me the best shots are,
1) The gray cat.
2) the orange kitten that needs a little taken off the top (see above )
3) the old red truck at the car show. ( If you could have shot a little wider and got the back of the truck with the full Chevrolet emblem, I think that shot would have been great.
So, to help with making shots the most interesting as they can be, focus on the composition and framing of a shot. Get low. Don't shoot everything from standing up and looking downwards. Don't include useless clutter in a shot, whether it be the side of a bridge or walkway you are shooting from ( The HOLY HDR shot ) or too much clutter around your subject (The Roof Top ) , refrain from always shooting from a high angle (Kittens on a chair, Cafe ) Watch your backgrounds. Imagine if you are shooting a piece of furniture that is just a tad retro looking but not too much. If you include a bunch of crap around the subject ( lets say a cordless phone on a side table next to the chair ) that automatically puts the subject into context to the viewer that it is a modern faux-vintage style couch. This may be good if thats your intention. However, if you remove the phone and just leave the table ( or shoot from another angle to exclude the phone ) you now leave the viewer room to interpret that shot however they want. Composition, framing and angles make or break shots.