Hi Linda,
I have a few remarks.
I actually like the background as it is. Making it darker would make it lose atmosphere and spatial suggestion. The background appears a bit warm, but it doesn't really bother me.
I sense a certain sharpness in the way you draw lines or the way you define the forms. For example the chin seems the end up in (almost) a corner. But I see this tendency to end up with sharply defined forms in more places. (Part of it is of course a personal touch, part of it is maybe something you could look at whether you want to adjust this or not.)
The way the white clothing on the left side makes an almost razor-sharp contrast with the blue pillows is a bit too sharp I think, it seems to distract from the face.
I like the brushwork. But I have a suggestion, the brushwork could have more effect if it is applied even thicker. After it has dried, why not put some real thick layers of paint with rough edges in the area of the white clothing? It would liven up that area even more (it's alive already). The hair and the pillows are other areas where thickly applied layers of paint can liven up the portrait even more. Thickly applied brushwork can make a painting seem to glow as if it's a light source in itself.
In first instance I had the feeling that he looked a little bit cross-eyed, but I'm not sure, it's not much anyway, but it's a feeling I have.
For some reason the squares of the pillow behind bothered me a bit. The structure doesn't really blend in with the rest of the painting.
The way you adjusted the background on the right side of his face and hair you did with a mixture that is different than the original back-ground (more white). It's a bit like smoke in the space where he is.
He looks very alive, I like the painting more each time I look at it.
"Great work!", "Nice job!"
Peter