how do you make it so that shadows are constantly shown on project64? sometimes his shadow is there sometimes it isn't

just set graphics settings to max...

i set anisotropic filtering and full-scene antialiasing to the max but his shadow isn't always there

Change your video plugin. Jabo's is known to have issues like this. GlideN64 is the one we recommend most. Just make sure to disable the framebuffer emulation. You might check out the Project 64 link in the Resources section, it has a pre-packaged build with all the plugins, as well as setup guides for all of it.