You have discovered the world wide web as a place for recourses. It is most important to know where to find the things you can not create yourself. Nice sky, light is very important, it can really make or brake your scene. But try to photoshop away the lens flare, you will never see a lens flare on a photo that was shot at night. Palms are ok, but I would have placed them more to the sides, so they do not pull your eyes to them The texture of the ground looks too fake. It is very hard to make realistic textures, and very important, realistic textures can also make or brake your scene. I had best results using photographs. Also add some more plants on the ground, and stones, perhaps an animal or some wood or something like that. It are the details that really make a scene realistic. Remember: recources, light, textures and DETAILS! Nice job for a first time by the way ;)