How to make game look good (aside from textures)

[Tempura]

So I understand the existence of HD textures for ut99. However, what settings should i edit for renderers? I use either openGL or xopengl.
How can i squeeze the most out of my renderers in terms of quality?

[OjitroC]

Have you read through this thread - it's long but does contain lots of useful info on, inter alia, renderer settings?