I can't tell if you new to tanking and need advice or just want a post about some other peoples ways to compare. So here are a few things i can think of off top of head.
Tab is a good way to cycle mobs, but make sure you set up your keys to tab for closest and another key for next npc. That will handle most targeting problems. Also lag can come into play so make sure your computer is up to task. (Thats right no phone line.

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Make sure you time combat arts with auto attack delays. And balance yourself with decent dps capabilities to hold onto aggro. Prob one mistake is to go so defensive that you give up some aggro control. More aggro control means higher dps for entire raid.
Try not to die no matter what it takes. If you have to use death saves or whatever doesn't matter just don't DIE. Cause we all know healers are afk eating some cake or pie.
Positioning is key so make sure you are good at positioning a mob and learn there pivot points. Also let people know when you are going to reposition.
Make sure you give a consistent countdown. Your raid prebuffs/wards etc. around your countdown so try to make it consistent.
Read about your class and make sure you have a raid tank or off tank setup. As a off tank you want as much snap aggro as you can get to grab mobs. Main tank you just gotta keep aggro and survive.
Learn mob strategies. Once you know a strategy for a mob it gets easier and easier. So take time to learn everything about the encounter and encourage others to do same.
Most this stuff you will here people say, "Well if your raid is good you don't have to worry about this or that." "Or we don't have to do that cause our nuts drag the floor they are so big". So take in about 50 percent of what they say cause you know 50 percent is absolute crap.
So finally.
Don't listen to anyone on eq2flames. Especially this post