My first toon was and is a LM (lvl 65 at present). I have 36 toons and I do play them all. I am a DM from the old days when we didn't have computers but simply our imaginations, a piece of plexiglass, some paper and few dice to play with.
The Lore Master is one of the hardest to wrap your head around, especially after playing the roll of group tank for a few days. You have to get your head out of the "charging head first into combat" mind set, which you should never do no matter who you think you are. You just can't do that with a LM.
One of the things I try to do when playing the LM role is to find a higher vantage point that gives me a view of the battle field if I can. This not only gives you a commanding view but you can better manage your group if you are removed from the melee. This can be tough depending on the terrain and nearly impossible in a run and gun situation, but do your best. Staying removed from the main group is what you should be doing in all situations.
You should never, and I do mean NEVER set your LM to Follow on a healer or any other toon in the group. It is certain death for you and the group. Stay above and removed from the group. If you are doing this correctly, your group should be asking "where are you" or "try to keep up" often. Think of it as playing hide and seek. Get use to it.
When applying buffs and pushing power to your fellows you should always use the fellowship icons in the group panel to select your fellows individually. This helps you keep control over what goes where and to whom. This also reduces the time it takes for you to deal everything out greatly, which in turn will free up more time to think about what your next move should be. If you must use an AoE like Sticky Tar or the like, place it in the best spot with plenty of room around it if possible and then get away from it. Get your tank to agro the boss or dmg dealer into it. It's not for you.
It can be difficult to think as the battle is in full swing and the situation is fluid. Give yourself more time when ever you can. Make sure the group understands what you are going to do and when BEFORE you enter.
Having your pet out can draw more agro to you then you want, but you may need someone to watch you back too. May I suggest a lynx for this specifically. I hear a lot about this seldom used pet. None of it good. But it is THE most stealthy of all your pets and deals an amazing amount of damage with a very high critical chance from stealth mode. Just make sure that the skill you want the pet to use first is selected by right clicking on it when you get them out. Then set the lynx to passive or guard mode and it will not draw agro hardly at all, but it will be there if you need it.
Know and fully understand ALL your pets and what they excel at. Most of all, feed them, and feed them often. There is no excuse for your pets not being buffed at all times when they are out. And that goes for the Lore Master's animals too. ;)
If your group does not look upon you as the leader of the group at all times, find a new group that knows how to follow. If you sucked at the role of Dungeon Master as a kid, find a new role to play. The Lore Master is the only role that has the word "Master" in it and the only reason we don't call them Dungeon Master is because that name was already taken. If you have not "mastered" the game and all the roles that the other toons are supposed to be doing at any given time, DON'T BE A LORE MASTER, PLEASE. You're giving the rest of us a bad rep.
I had to rescue a lvl 85 Guardian in Dunland the other day. Afterwards he asked me not to tell anyone because he would never live it down (having to be rescued by a light armored LM). I told him to check his stats and be glad that a real Lore Master was there to save his hide. We are the only ones who care enough about all of you to do it. Remember that.
Check your Toon's stats, virtues, etc. and keep up on them. DO YOUR DEEDS! Might will never be good on a LM no mater how much you want it to be. Everything posted here by the other players is very good advice, so take it. You should have an LI staff and book set up for all three of your trait tree Specifications specifically. It does you no good to have a LI staff and book set up for the fire trait tree while in Master of Beasts trait tree. Don't just max out a LI weapon and say that is good enough. It's not! READ, READ and READ till your eyes bleed.
But most of all;
Lead, follow, or get the hell out of the way!