Not bad, you're trying lots of different subjects and even some good starts on using elements to drive your composition. Couple of pointers, ease back on the zoom a little. No need to ram the lens into a subject to isolate it. Lots of practice will give you ideas on how to use the elements and light around you to naturally highlight something interesting. You don't have zoom lenses in your eyes so just think to yourself, "I spotted that interesting thing over there so what stuff around it made me look at that thing and want a picture of it?".
Now you're putting basic compositions together and capturing them you need to start getting up to speed on processing your images to bring out the contrast and interesting colours you see. Every image from every digital camera always looks flat, you'd hate to see how flat my RAWs look when they first come off camera. Have a dig about in some magazines and websites see what you can find about first steps in basic post-processing that will lift an image's tones and colours up a little. Once you get a feeling for it, it gives you lots of ideas when you're out there looking for shots to take. I've always found post-processing knowledge adds something to my actual shooting, gives me even more ideas about things I can do with the shots that I otherwise might not consider.
You aren't so bad as you think at photography. Maybe you should taking more photos about different theme. Just think what do you want to show people to make them interested. If you want to get inspiration for taking photos- let's surf on the deviantART and find artists who will make you more self-confident. And the last one- read maaaaaaany posts and tutorials about photography. It's really, really helpful! I hope you will better, better and better in your interest. Good luck!
“Your first 10,000 photographs are your worst." – Henri Cartier-Bresson
The key is to constantly be creating photographs. Practice is crucial. Try to experiment with portrait photography, landscapes, and the works. If you look up different photography techniques such as levitation, HDR, or even light leaks you can then practice with that. You want to be able to make a narrative within your shots. Different techniques can make that easier. (:
I am a mainly self-taught hobbyist, but I strongly encourage taking a class. Photography assignments are a great help.
Your composition is fantastic, you've a good eye for it, but as qwstarplayer has mentioned, they need a little bit of post-process. The colours are a bit flat and the image doesn't pop. Yet don't overdo it. Deepen some shadows, boost some colours a little but you're working with a naturally beautiful place, so it won't need a lot of adjustment. Experiment with different lighting through the trees etc. Great work! Keep it up!
Basically don't be afraid to get weird, like taking pictures where you never would think of taking pictures (like a grocery store or a superstore) or tilting your camera a little (I love different camera angles).
Also, take your camera everywhere. EVERYWHERE. But be careful. I think my camera was snagged at the mall.
Take lots of pictures of different things, shoot what you love and read lots of tutorials (and there's a wealth of knowledge amongst the photographers on this forum). But also don't be afraid to step outside of your boundaries - you might do a shoot, love the work you did but realize it's just not for you but it's still a chance to practice shooting and post editing. Are you trying to get into uni for photography?