revenge ? Depends... but usually it would be done where it hurts most and in a way so innocent the person would never thought it is revenge and link me to it.
Say for example, this person love his car. You wanna revenge ...
Wait a couple of weeks if there was an event that made you swear revenge against the person. ie : person offended you badly at a certain thing. You have all the time in the world and remember, revenge is sweet and needs to be savoured. Never ever take revenge in the way the person delievered his insult. Its just copy cat, unsatisfactory and shows how unimaginative you are. Ok it proves you are not as wicked as I am.
For people who have car, you might for instance spoil the pain work. Another day put a coke can under the wheels. Or even vomit especially when you are drunk, onto the car or the air vent. Use your imagination what happens to all these things.
There are things you can do with mail accounts, personal information and etc. Hell, there's always more than 1 way to get back. So don't be obvious and do a direct confrontation, always flank and attack when they least suspected. And feign innocence and pretend to care ... Laugh/gloat in private and never let people who are not good at acting know what the hell you are doing.

Ok you ask, I tell. Not that I do the above but its a series of pranks people pull in my secondary days. I did some stuff but ain't gonna reveal it here. But I guess most people would tell you the politically correct and expected answer isn't it. Its always very serious thing that would warrent these actions. But ppl will just to conclusion fairly or unfairly.. but who cares.