Sight = seeing stuff
Because of my lousy sight, I must wear glasses.
I could hardly believe the sight that greeted me when I opened the door.
Site = a place (physical or "web...")
Sacramento will be the site of the next National Down Syndrome Congress conference.
The webmaster completed his total redesign of the site in under three weeks.
Cite = refer to
The judges cited three precedents in the text of their ruling.
If you do not cite your references, you will be accused of plagiarism.