Have you done a full render of you model yet, or are these screenshots of the modeling view port? If you do a full render, the result can be better, plus you can choose the resolution and scale of your image. You can also save the rendered image directly without doing a screen capture.
Here's a comparison between a screenshot of the view port in the "rendered" setting and the image saved from the full render for the project I just finished (in keeping with the theme of the last model, it is a Rebel snowspeeder).
First is the screenshot.
View attachment 220391
And now the full render image:
View attachment 220390
I have a habit of doing test renders as I work on my model in order to get a better feel for what the final look will be.
Quick disclaimer: While the helmets for the pilots were done in Blender, the actual pilots weren't. They were created in DAZ 3D Studio and imported as wavefront(.obj) objects. DAZ 3D has pre-loaded posable human figures which make things a lot easier than making them with Blender.