1) Read your skill descriptions to understand what they do, how long they last and how long they are on cooldown.
2) Practice using each and every skill you have so you understand how it works with/against other skills.
3) Don't be afraid to try something you think you can't do. A level 12 LM can kill the level 15 elite master warg that wanders around Chetwood. You have to understand your skills to do it but if you understand them it is fairly easy to do. There are many things like this as you level up that you can do solo both out in the open and in group instances.
4) Do not think that the way you do things is the only way that a LM can get the job done. There are many tricks of the trade to learn on a LM and it always pays to watch how somebody else handles a challenge.
I'd say Tinker because they can craft many LM specific jewellry pieces as well as make food for your pets.
Character Development -
1) Learn all your skills and work on getting you class deeds done along the way.
2) Retrait on occasion to see how different class traits effect your play style as well as evaluate how they may help in a group situation.
3) Duo with all of the other classes when you can to see how your skills aid that class and how that class can affect your play style.
4) Step out of the box and lead fellowships and raids. It is always easier to use your class to the best of your abilities if you are deciding what needs cc'd, what needs pulled and how the group make up will handle it.
The most important thing - have fun!
Elendilmir - Officer of the Mithril Crowns (The Oldest Kinship in LOTRO)
"It doesn't matter how well you play, only how good you look while playing."