-Make sure the resolution is the lowest you can tolerate within your monitor's aspect ratio. (for example, running 1920x1080 will be much more taxing than running 1280x720. The minimum recommendations probably aren't aimed at more than low resolutions in any case)

-Make sure AA (anti aliasing) is off and AF (anisotropic filtering) is on low levels

-Make sure all view distances are set to minimum from the advanced graphics menu

-If the above doesn't work (which is likely to already be the case, just making sure that you've done those, I don't know how well you know these things), you can try one of the multiple performance tweaks, such as the TESV acceleration layer, which are a bit hit / miss. You might benefit from it. TESV Acceleration Layer at Skyrim Nexus - Skyrim Mods and community


This is, assuming that your computer does not have a decent enough graphics card / CPU for it. I don't know what you're running, a little bit of clarification would be nice.