The last photo, the against-the-light shot of the nesting birds. It's got good silhouette on the lft bird, less impressive silhouette on the right hand side bird. Shots like that are mostyl about "gesture", meaning not hand gestures, but how the person or animal "looks", and what it is doing: standing, walking, wings spread, neck craned or head tilted, etc.,etc.. Silhouette shots like that are ones where you have to catch something at just the right time, with the right look, perhaps even waiting 5,10,15 minutes for something really good to happen.
As far as sharpness at twilight: the liught level is low, so it takes a very good lens and sometimes higher ISO levels to get a truly sharp, crisp image at that time of the day. A monopod or tripod can help steady the camera, while you wait for something really special to happen.
I'd say, keep on shooting, keep working at photography, keep on looking at the world, keep on thinking about how to show things.