Now this isn't to say that there are not good players on during the day, and that every bad player should be kicked. Sometimes all that's needed is a friendly hand to help out -- in fact in the vast majority of time that's all that's needed. You'd be amazed at how simple it is to just say to someone "Hey, can you do X instead of Y? It'd help us make this run faster and smoother." People love getting tips like that, and most of the people you meet respond wonderfully.
But for the other group that doesn't... well, it's time for the vote kick. Throughout the last month I've perfected the method of getting a successful vote kick or correcting the problem. Here's my five step process;
Step 1: Politely ask the player to fix the problem
Really, most of the time, this will solve the issue. People don't want to be a bad player -- and even though there's a ton of WoW information and strats around, most don't read them. Just asking them to fix something will usually get their brain working on solving the problem on their own. Be sure to do it politely too -- and not fake politeness either.
Step 2: Politely tell the player how to fix the problem
If asking nice the first time doesn't get you anywhere, just tell them what to do -- still politely though. Sometimes the problem player really might not know what he's doing wrong. The easiest way to fix this is to just use your own smarts and give 'em a hand. Sure, you're essentially playing for the guy -- but that's better than wiping and having to spend all that excess time messing around.
Step 3: Ask the player again, maybe not as polite, to fix the problem
There's a way to be assertive and not be a jerk. That way is what I'm talking about here. You know that tone your father took with you when you were fighting with your brother too much? Or were being a bit too annoying during reruns of The Rockford Files? That's the tone you want to take in your next step. Respectful, but maybe not the nicest way possible. Sometimes this lets players know that you're serious -- but more importantly it shows to your other group members that you're still trying to work with the problem player.
Step 4: Warn the player that he needs to fix his problem, or else a kick
Here's where you cross into somewhat dangerous territory. And if you've reached this point then chances are step 5 is going to come around too. But this step? This step is all about letting your group members know that this guy is really causing a problem and needs to go. Sometimes you'll do this step and suddenly a vote kick will appear from one of your other group members that is equally annoyed as you are. This happens pretty often, actually.
The key here, and really throughout this whole five step process, is to just be nice and professional. If you stoop to the problem player's level then you'll be viewed as no better than him. So don't -- stay above the fray, and you'll end up without the guy soon enough.
Step 5: Tell the group you're going to kick him, and why. Then vote kick.
Finally you've reached the moment where you can't stand the guy anymore -- you've tried everything. You've been nice, you've told him how to fix the problem, you've asked him several times, and you've even given him a warning. The final step is to just calmly and politely type into chat why you're initiating the vote kick, ask for your group's assistance so you can move on, and then do it.
I have never had this five step method fail. Either the problem is solved or the group vote kicks the person out. The only time it doesn't apply is when you've got a group full of people from the same guild/realm who are just intent on being trolls; in that case you might as well just drop and re-queue.
And again just to reiterate -- the key here is to always be professional. You can be professional and be assertive while not being a bright shiny ray of sunshine; just never be mean, don't curse, and you'll find yourself without that one bad group member soon enough.