I did a little bit more to make it seem like night and maybe give it some more depth, I wasn't satisfied with my little color-over. I dunno what else to do at this point, and I'm honestly just flying blind at this, so I will just call it good and let you explore further from here. Hopefully all these examples will give you plenty of ideas and you'll zone in on a technique. As everyone has said, layers can be your friend, I hated them too when I first was introduced to them. They get easier to work with the more you do it, and if you do decide to go with photoshop I highly recommend reading some kind of tutorial on the layer styles, blending options, and the use of adjustment layers. Good luck!
Here's what I did.
1. I refined all the layers and reconfigured them by copy-merging them all to new ones so as to remove the linear-burn layers. That way I could work on them, without them blending into each other and still preserving the basic color and line work from before.
2. I added some further shading to the house, the tree, the trash can, and the porch rail.
3. I added shadows for some of the objects, like the tree, trash can, and mailbox.
4. I added more light, then erased the light to make the shadow for the porch rail. (inspired by privateer's edit! ^^ )
5. I used a curve adjustment layer to pull out some of the darker lines from the background but left the mailbox, trash can, and tree somewhat alone.
6. Finally, I slapped on a color balance adjustment layer to give the scene a bluer tint.

Here's what I did.
1. I refined all the layers and reconfigured them by copy-merging them all to new ones so as to remove the linear-burn layers. That way I could work on them, without them blending into each other and still preserving the basic color and line work from before.
2. I added some further shading to the house, the tree, the trash can, and the porch rail.
3. I added shadows for some of the objects, like the tree, trash can, and mailbox.
4. I added more light, then erased the light to make the shadow for the porch rail. (inspired by privateer's edit! ^^ )
5. I used a curve adjustment layer to pull out some of the darker lines from the background but left the mailbox, trash can, and tree somewhat alone.
6. Finally, I slapped on a color balance adjustment layer to give the scene a bluer tint.
