Looking for advice on improving sharpness (1 Viewer)

As I look around online of bird pics of the same setup I use, T2I + 100-400, I cant help but notice the sharpness and contrast that others get versus my own shots. I can understand low loght conditions, but even when I have ample light, I still lack the incredible sharpness and contrast I see in others pics. Heres a few examples, one in lower light and one in bright sunlight. The pics are decent enough, but lack the contrast and sharpness I see in other similar pics. Any advice on improving my pics? Thanks

I've had a go at one of your shots, and possibly it's a little improved. (Raised contrast a little, and applied a little USM sharpness.)

Have you checked whether your camera and lens are focusing correctly together at the distances you use when shooting birds? I frequently check my kit by shooting something like a high contrast target sitting on a brick, and then check whether the ground/grass etc. is sharp in the plane of the target, closer or further away. I frequently need to make small adjustments for best results.

No I havent tried that yet. Ill give it a go and see what I come up with. Thanks!

I'm led to believe that particular lens might give sharper images at f8 rather than wide open. Other considerations are crop size, shutter speed and stability of course. As you say, in lower light the images are less likely to jump out at you.