Render is weak compared to viewport

Can someone tell me what I should do to this files render settings to improve the result?
At the moment the viewport view is far better than the render.


Close up:


Thanks.

Increase render size (currently 960 x 540 pixels) and the rendered object is only a tiny part of that image
Increase the lamp strength/distance to lighten the scene

Thanks Richard.
Render Size - is that the same as Resolution? I’m not sure where the 960 x 540 setting is:


Ah! never mind, I just saw the 50% slider.
This is where I’m at, after doing as you said and scaling things down as well.


This is at 3000 x 2000 px:


Attachments


50% of what you marked with that arrow shape… Make it 100%