Communicate with your group calmly and understandably. You are the first to enter a fight, so make sure you type out what you plan on doing. Like others have said, the best way to determine a speed run is to just ask at the beginning. Unless you joined a PF with specifically that purpose, it's best to make sure.

If you are going to do a certain method for handling a pull or a boss, make sure that's made clear beforehand. Lost City of Amdapor is a good example of this; make sure you know who is going to handle doors before entering. Don't assume anything of a group if there are multiple methods.

If people are making mistakes, such as attacking the wrong mob, or pulling hate, politely ask them to stop. If they refuse or give you problems, kick/report them asap, there's no reason for that. If you were polite, so should they.