Focus on content, not on the other editor. Wikipedia is built upon the principle of representing views fairly, proportionately and without bias. When you find a passage in an article biased or inaccurate, improve it if you can. If that is not possible, and you disagree completely with a point of view expressed in an article, think twice before simply deleting it. Rather, balance it with your side of the story. Make sure that you provide reliable sources. Unreferenced text may be tagged or deleted - see Wikipedia:Verifiability.
Always explain your changes, especially when you want other people to agree with you. If you can say it in one line, use the edit summary; for longer explanations, use the talk page and add "see talk" to the edit summary.
Writing according to the "perfect article guidelines" and following the NPOV policy can help you write "defensively", and limit your own bias in your writing.
[edit] Stay cool
Policy shortcut:
WP:DISENGAGE
Most situations are not urgent. Please give both you and the other party some time. Often it helps to just take a deep breath and sleep over it. Don't worry! You always can fix the problem later. (You can go back to the page history of an article at any time, to find the version of the article that you last worked on, and compare that to the current version to see whether there are still things that you'd like put in or taken out.)
Take a long term view. In due course you will probably be able to return and carry on editing it, when the previous problems no longer exist and the editor you were in dispute with might themselves move on. In the meantime the disputed article will evolve, other editors may become interested and they will have different perspectives if the issue comes up again.
This is particularly helpful when disputing with new users as it gives them a chance to familiarize themselves with Wikipedia's policy and culture. Focus your contributions on another article where you can make constructive progress.
[edit] Discussing with the other party
Try to stay in the top three sections of this hierarchy.Further information: Wikipedia:Negotiation
Policy shortcut:
WP:DR#Discuss
Discuss the issue on a talk page. Never carry on a dispute on the article page itself. Either contact the other party on that user's talk page, or use the talk page associated with the article in question. (You may even post the proposed content on the talk page.)
When discussing an issue, remember to stay cool. If you encounter rude or inappropriate behavior, resist the temptation to respond unkindly, and do not make personal attacks. Take the other person's perspective into account and try to reach a compromise. Assume that the other person is acting in good faith unless you have clear evidence to the contrary.
Both at this stage and throughout the dispute resolution process, talking to other parties is not simply a formality to be satisfied before moving on to the next forum. Failure to pursue discussion in good faith shows that you are trying to escalate the dispute instead of resolving it. This will make people less sympathetic to your position and may prevent you from effectively using later stages in dispute resolution. In contrast, sustained discussion and serious negotiation between the parties, even if not immediately successful, shows that you are interested in finding a solution that fits within Wikipedia policies.
[edit] Truce
Consider negotiating a truce - see Wikipedia:Truce. This is also important if you intend to solicit outside opinions because it allows others to consider the issue fairly without the confusion of ongoing edits.
[edit] Turn to others for help
If the previous steps fail to resolve the dispute, try one of the following methods. Which ones you choose and in what order depends on the nature of the dispute and the preferences of people involved.
[edit] Editor assistance
Editor assistance helps editors find someone experienced to provide you one-on-one advice and feedback. While not a required part of dispute resolution, it is designed to help you understand how to clearly and civilly express your views and work toward consensus. You may request an assistant's help at any time, whether you're involved in dispute resolution or not. Assistants can also help you find the best way to resolve your dispute or issue.
[edit] Ask for a third opinion
If you need neutral outside opinions in a dispute involving only two editors, turn to Wikipedia:Third opinion.
[edit] Ask about the subject
Ask at a subject-specific Wikipedia:WikiProject talk page. Usually, such projects are listed on top of the article talk page.
[edit] Ask about a policy
Ask at a policy talk page relevant to the issue.
[edit] Ask for help at a relevant noticeboard
If your dispute is related to one of the following topics, you may wish to post about it in one of these locations, to get the opinions of other editors familiar with similar disputes:
Reliable Sources noticeboard - for discussion of whether or not a source is reliable
No Original Research noticeboard - to ask about material that might be original research or original synthesis.
Conflict of Interest noticeboard - to raise alerts about possible COI
Suspected sockpuppets noticeboard - to ask for help in tracking down sockpuppets
Biographies of Living Persons noticeboard - to raise alerts about problems with a living person's biography
Fringe theories noticeboard - to report theories that may be being given undue weight
Fiction noticeboard - for issues related to topics about works of fiction
[edit] For incivility
Turn to Wikipedia:Wikiquette alerts for problems with uncivil editors.
[edit] Request a comment
Turn to Wikipedia:Requests for comment, the main avenue for disputes about user conduct. Note that Request for Comment is normally a necessary step before Arbitration can be sought, and is normally for disputes about User Conduct, although you can also request comments on articles, templates or categories.
[edit] Informal mediation
If things are getting a bit tricky, it might be useful to ask some cool heads to look in and help out. Sometimes editors who provide third opinions or respond to requests for comments may be willing to help mediate a dispute, if it is requested. The Mediation Cabal can also assist in settling disputes without turning to formal mediation. Note that Mediation is normally for disputes about Article Content.
[edit] Formal mediation
Request mediation of the dispute. Mediation is a voluntary process in which a neutral person works with the parties to a dispute. The mediator helps guide the parties into reaching an agreement that can be acceptable to everyone. When requesting formal mediation, be prepared to show that you tried to resolve the dispute using the steps listed above, and that all parties to the dispute are in agreement to mediate. Mediation cannot take place if all parties are not willing to take part. Again, note that Mediation is normally for disputes about Article Content.
[edit] Conduct a survey
If consensus is difficult to gauge from discussion alone, consider conducting a survey of opinion to clarify the issues in the discussion. Note that a survey cannot generate consensus, but is helpful for understanding it. Similarly, if you believe that users are ignoring a consensus, a survey cannot force those users to accept your proposed consensus -- although a survey might assist users in understanding the balance of opinions and reasons for those opinions on a given dispute, it can also easily degenerate into an argument over whether a particular survey is fairly constructed or representative. See Wikipedia:Polling is not a substitute for discussion for reasons why discussion is necessary and superior to voting.
[edit] If the situation is urgent
If a situation needs quick attention, report it to WP:AN or ask for page protection. They will take it from there.
[edit] Last resort: Arbitration
Further information: Wikipedia:Arbitration Committee, Wikipedia:Arbitration policy, and Wikipedia:Requests for arbitration
If you have taken all other reasonable steps to resolve the dispute, and the dispute is not over the content of an article, you can request Arbitration. Be prepared to show that you tried to resolve the dispute by other means. Arbitration differs from Mediation in that the Arbitration Committee will consider the case and issue a decision, instead of merely assisting the parties in reaching an agreement. If the issue is decided by Arbitration, you will be expected to abide by the result. If the case involves serious user misconduct, Arbitration may result in a number of serious consequences up to totally banning someone from editing, as laid out in the Arbitration policy. Note that Arbitration is normally for disputes about user conduct, while Mediation is normally for disputes about article content.