The photos are technically speaking, quite good. Vibrant colours, focused, etc. However....
1) palm trees with coloured sky. Love the tones of the sky, but...Eh, my eyes aren't pulled to something. Rule of thirds. The tones of the sky are good, maybe you could crop it so it's more influencing.
2) Trees, building. No. There is no one "thing" here. If you were trying for the building, you've got trees in the way! If you were trying for the trees, you've got an ugly building in the background! There is nothing interesting here. However, the building has some interesting architecture. Go back and try shooting just the building, from interesting angles. It might produce some very symmetrical, abstract art. But have a focus and an influence!
3) Palms in a line. Not bad. However, change your angle a little more. You've got lots of tree to the left of the centre, and sky to the right. Moving to the left would fill out the frame more. Moving to the right would make the trees all dissapear, and might make an interesting shot. One tree, lots of leaves? Sky is exposed decently, but the trees are very underexposed. Maybe, try shooting multiples at different exposures and combining them, so both are well exposed? But first, try a little different angle. This shot isn't bad, it's better than #2.
4) Masterlock. Everyone else might be taking pictures of them, but I've never taken a shot of a lock, it doesn't strike me as cliche as another poster found it. The blue seems on one hand, vibrant, on another hand, too vibrant, almost photoshopped. However, I do like the shades of gray in this one. Notice, the angle of the lock almost splits the image into two triangles. This is an effect similar to the rule of thirds which often gives a good image. I like this one. I don't love it, but I can't find much wrong with it. Maybe, go back and shoot more of this lock from different angles, to get something that the other guy will find more unique, because I really do love the colours and shades in this image.
5) palm. This one is close to being good.
Try moving the palm a little more to the right, so it lines up better with the rule of thirds. however, it's not too bad where it is. You got lense flare, but it's in the corner. I don't love it, but I don't hate it. It combines well with the orange on the fronds. The sky is pretty good too, but you could try adjusting the colour balance so it pops out at your more, then it'll be better for a desktop. This is a good image.
See, you are lucky. I have to pay $3 for a roll of film and $4 to get it developed. It's only 24 shots, and it's not like I can jsut sit there and play with a subject until I get a good shot
Not to mention, all I've got is manual focus lenses
Your photography isn't bad, but like another poster said, rule of thirds and a clear subject (reason for the picture) are two things you need to work on.