graphics

I can run garrys mod with no lag at full setting for everthing,but it still doesnt look good like videos ive seen on youtube and pictures. How can I make it better?

Mind showing a video or picture?

Resolution.

Anti ailising and Antistopic filter bloom and mat_picmip -10 in console is all I can think of

Some videos use post-processing effects to make then appear better.

Videos might have been graphically enhanced. Pictures could be sharpened with Photoshop.

Either that, or high resolution textures.