Looks good, but I think you should try to match the colours of the background with those of the render. For example by copying the render a lot of timesand pasting them on one layer to fill the layer, then run effects on that layer. that would already help with blending the render. There are a lot of ways to blend your render, I'll just give 2 now. - Copy your render and smudge it - Use the same values to change the colour of your render and background. If you want to know more ways, do full sig tutorials as they also include blending the render.