hi guys,
my aim is to make this photorealistic. if anyone has an idea how to make it more that way, spit it out 
render is AO with an foto as sky, there is an area light “north” of the picture.
the leather bumpmap looks a bit too smooth imho, but the resolution should be high enough. i’ll try disabling antialias for the textures next render.
A few things: the glare off the table top is realistic, but a professional photographer would be unlikely to set up the lighting that way, since it detracts from the book and creates those unsightly “zones” of different color on the tabletop.
The bump on the leather looks deep enough, but the scale looks a bit large. You might try tweaking the xyz size for that texture in the Map Input panel.
Finally, the brass corner tabs look too small. I’ve got a leather portfolio with brass tabs. The overall size is around 24x32 cm, the corner tabs extend 2 1/2 cm from the corners. Granted, a portfolio takes more of a beating than a book, so the reinforcement would be sturdier, but the tabs just seem too small to me.
Try a little discolouration, a few stains. Very faint, but if you’re going for an old book, unless it’s been REALLY well taken care of, there are bound to be some dings and peeling spots.
I agree with Orinoco … first try to set up the lighting as a professional photographer would do, then worry about making it look good under those lights.
Under the lighting as it is set up right now, nothing will look good. And that’s not fair to your work…