Hola! I think the concept is pretty cool tbh! you have a couple things warring against you. the main one in my opinion is actually the positioning of the hand for several reasons.
1. It almost instantaneously makes the image look flat.
2. The finger the bird is perched on is too long in comparison to the other fingers. Your middle finger should be the longest.
3. And if the bird were perched on that finger, the fingers behind the bird would be at a different angle to compensate for the space the bird is taking up.
try playing with hand positions
like this:
Also, your background is fairly busy, so it's competing with the image in front of it. Because the concept you have going is really cool, if i were you i'd want to have it be my focal point! you can do that by slightly SLIGHTLY blurring the background to cause a separation in background and foreground images
The lighting issue is tough in your case because your light source is coming from the upper left hand corner. Which, with the hand being in the position that it is, would mean that it's blocking the majority of the light from hitting the bird, and whatever shadow the bird cast would actually fall to the bottom right of the bird, rather than to the upper left:
it would also mean brightening the part of the hand nearest to the light, right now it's shadowed:
Clare is totally right in that you're going to have some natural light just because it's in the day time. But even still, the photo isn't really bright. Both the hand and the bird should match the setting of the scene. in this case you have a yellow and green hue going on with maybe a tint of red. your hand and bird are more yellow and red with a tint of green
easy fix, you just need to put a color balance layer on top of it and you can pretty easily adjust the whole piece to match itself..
i used the following for the color balance layer:
Shadows:
+12
+22
-19
Midtones:
+13
-6
-40
Highlights:
+8
-15
-36
From there, you can use your dodge and burn tool to emphasize shadowed areas or create shadows in places that didn't originally have them. Same goes for lighting. the bird would only have a touch of light around it's breast and neck:
sometimes burning images too much will leave a weird red trail behind, in which case it's better to just create a new layer, set it on multiply, use a soft brush set at 10% opacity and paint over the top of the image with a dark green for more dramatic shadows. Same thing for highlights, sometimes it's better to just use a white brush, turn it's opacity to like 10% or something and lightly build highlight areas:
hope that helps