[waylon]

Lookin' pretty good. The main thing that stands out at me is that the perspective doesn't look right. It's a combination of two things, I think. First, well, your vanishing points are inconsistent. That'll do it any time. But on top of that, you've got the same level of detail going on in the foreground as in the background. The grass at the front looks the same as the grass 30 meters away.

Anyway, both of those are pretty vital, which means they'd make the biggest difference if they were fixed, but they're also the most work. One other thing you could play with that would help the perspective is the atmosphere. As things get farther away, they get bluer, lighter, and less saturated. So the pyramid and the trees in the distance would be more heavily affected.

Just something to play with. Good luck.

[zenonithus]

This has some nice qualitys. Though the sky looks very unatural in colour. Desaturating it may help.

[EvilKosh]

Here is a painting I did... Let me know what you think.