I want to add sun light coming through the window and then have sun light reflected on the bed. But I just can't seem to figure out how to do it.
(http://www.pictureshoster.com/files/7rerbxl4ekgxxcmeqwr.png)
Well, what exactly are you having trouble with? It's a pretty easy effect to achieve, especially if you're not bothered about it beign correct. Just paint some beams of light from the corners of the window and drop some light on the bed (it's better to do it on a separate layer), then erase some of the light on the bed where there will be shadows from the vertical planks and voila. You can mess around a bit with the layer's opacity and blending mode to get a result you like.
I'd also advise on paying more attention to the light sources - you have a window and a lamp here, but they have almost no effect on how the things in the room are lit - they simply glow a bit, while in reality they should define all of the shapes around them. It's a pretty nice-looking background, though.
Here's a 5-minute edit:
(http://i.imgur.com/dKBft.png)
Thanks for the example. I was so stuck on getting it perfect that I can see that it was a waste of time and I should just wen't on and did it. Also thanks for point out the light sources. I sometimes don't notice them all or how long they are.