Recommendation #1. Never pick a fight with a super famous celebrity. Why? Because when and if they Google their name your website will be lost in a long list of websites both praising them and dissing them. Plus super famous celebrities are being dissed constantly so you'd really be piling on the bandwagon and its unnecessary.
Thus ideally what you want to do is pick a fight with someone who is vaguely famous or semi famous, someone who is an egomaniac and Googles their own name regularly.
Recommendation #2. Research your target. Don't just pick them because they stuck their foot in their mouth more than once. You should try and determine how whether this person is a genuine scumbag or whether they just maybe a whoops.
ie. Comedian Michael Richards losing his temper at hecklers and using the N word. That was a BIG whoops and he later apologized for it. Another example is Mel Gibson's drunken anti-Israel rant, blaming Israel for why there is war in the Middle East, something which he later apologized for. These are extreme examples of sticking your foot in your mouth.
No, what I mean is you should only go after people who are unrepentant sexist pigs. Meaning they don't apologize, they refuse to admit their guilt and they instead continue to consistently make sexist comments.
One way to determine who these people are is to visit anti feminist websites or Facebook groups and track which people are saying bad things about women or feminists.
Recommendation #3. Stay local if you can. ie. The local mayor, city councilor, MP or pseudo-celebrity makes a much better target.
ie. I would love to go after Lord Maurice Glasman (British House of Lords) for making a variety of comments about immigrants in the UK, but he hasn't said anything about women so I am picking my battles here.
Recommendation #4. Don't bother with them if you don't REALLY despise them. You will get bored quickly of arguing / picking a fight with someone who is kinda blah in the first place.
Recommendation #5. Email them directly and keep copies of all their responses. You are looking for the angry belligerent tidbit where they show their true colours, but remember to...
Recommendation #6. Always stick to the TRUTH! Your argument against them has to be credible. Don't go making up phony quotes. Honesty is the best policy.
Recommendation #7. Video is even better. Catch them on video using the C word or something like that and their a** is grass!
Recommendation #8. Avoid excessive name calling and losing your temper. Keep your argument based on reason, logic and facts. Its much harder to argue against facts.\\
Recommendation #9. Remember your goal is to make this discussion public. ie. A message board may be a good place to start.
Recommendation #10. There are pros and cons to going after someone who is stubborn. Pro, they're likely to say a variety of stupid things out of anger / sheer stubbornness. Con, this isn't an argument you will win because they will never admit defeat. Your goal therefore is to bombard them with enough facts and well reasoned arguments that they eventually give up talking to you, even though they refuse to concede they were wrong.
While it is sometimes fun to ridicule their poor grammar / spelling / lack of brain power, don't keep bringing up their lack of intelligence. Throwing insults won't win the argument. Your goal is to unveil their bigotry so that other people can see what they're doing is wrong and then make their own decision whether that person deserves to be ostracized.
If they send you hatemail first (ie. they are picking a fight with you) try and research who they are before responding to their hatemail.
Don't say anything you might later regret. If you stick to the truth you can't go wrong.