I like them all and especially the last one. If you can, reduce your exposure times so you can get richer colours. Bright sun so easily burns them out. And best of all, shoot early in the morning or late in the afternoon, during the photographer's 'golden hour'. So called because the light is softer and from the side and colours are so much more beautiful at that time too. Portraits come out better too because you don't have hard shadows on people's faces.

I have a vague feeling that if you zoom in a bit more and fill a bit more of the frame with the subject of your images they will 'pop' a bit more too. Be brave, don't leave room for cropping! For me, your composition works well, I just want everything to be a bit closer, so I can see more of what the photo is about. So less background, more star attraction.

Hope this makes sense, and it's only my ideas, just keep enjoying yourself as the best way to take great photos is simply to take lots of photos, and you soon decide what you like.