Areas for improvement on my photography skills?

I'm a teenager from Singapore and i'm starting to take photos more and more often as it really captures memories that may not be remembered as time pass by. I recently got a Nikon D3100 kit, 18-55mm. And that is the only lens i have. So here are the photos I have taken, it may not be good but I'm still learning. Would love to know where and how can i improve as photography is really my hobby and i would love to learn more about it. You all may want to follow me on instagram and my instagram name is tanzhengyuan Here are some of my photos, feel free to tell me where can I improve on as I'm still new and learning.

*Some of the photos are taken with my iPhone 5, I don't use Photoshop or other software on my computer. The only editing software I use are snapseed, afterlight and vscocam on the apple store of my iPhone.*

The snaps you took on your phone are very poor quality - like this one: and this one:

Some of them are just plain boring and pointless like this one:

And you are adding too many effects to most of your photos.

Mobile phones don't take good images. Sure they are fine for snaps when you find yourself without a camera, but they are no good for real photography.