Turn down shadows and shaders in your settings as they have the biggest impact on performance. Lowering your draw distance will reduce VRAM usage but may cause noticeable lag while you're moving quickly.
Cap your fps to 60, so your computer is not overloading to achieve unrealistic goals as well. The only reason you'd want to go higher than 60 is if your monitor supports a higher refresh rate. Ingame FPS should be capped to your monitor's refresh rate. Any frames in excess will not benefit you in any way.
If you provide me your full system's specs, I can help you further with your settings. Download Speccy and screenshot the results.