As far as not pulling multiples to your group that's important to single as much as possible or rather, as much is required.

If you're in a group that can handle 2 or maybe 3 then pull that instead. However know the group first and what it's capable of.

Also when pulling keep a timer or pull in a recognizable pattern. Sounds basic I know, but I've been with pullers that just pull whatever and that works for a while until they haven't pulled for a while from a certain area, then they get aggro for 4 or 5 mobs after they pulled what looked like a single. Bad pathing + pulling a larger area than what the group can hold typically leads to this it seems.

rofl