They are good
The biggest thing is the composition, so if you learn when it is okay to center, and when to use thirds, etc, you will be able to go a notch further
http://en.wikipedia.org/wiki/Rule_of_thirds
The rule of thirds isnt really a 'rule' you always need to follow, but just a way you can compose photos. People who dont know about thirds might always split everything in half, or center everything, like you did. Then people learn about thirds, and just as bad, they make EVERY photo to thirds. The best thing is to learn many different ways to compose a photo, always learning new ways to compose, and use what you find best. Improvise, try new angles, shoot from really low, always try something new. This will set you apart and you will start to develope you own style.
Here is what I would have done,
The portrait, I would have put the guy in the left of the frame, and shot really low to the ground, to give it a lot of depth and foreground. You would notice the person, then your interest would go to the buildings in the back
The next 4 landscapes, I would have done the same thing, but this time I would have tryed to find something small in the foreground, like a rock or grasses or something to give them depth.
The last one I would have went with thirds and placed it off to the side, or if you could get up close to the lighthouse, I would have zoomed in on the top, or shot up at it, making it look tall, or included some of the ocean in the shot.
Before you snap a photo, stand there and look at it, visualize how you want it to look on the computer/paper. Once you get the visual, ideas in your head, THEN you start trying to capture that with the camera. As you are walking around stop to look at it from different angles and try revisualizing it. Your first attempts are usually not your best, so try many different compositions of the same subject and learn what works