How can I implement like functionality on my web page, without user login?

What kind of possibilities are there for adding like-functionality to my web page, without the user logging in?

I know I could log IP, use cookies and/or local storage, and that I probably will not have the possibility to avoid people liking more than once, if they really want to.

I want to avoid making it too easy for an average web user to vote multiple times, how can I give them a hard time?