When it comes to this class, you'll find that one of the main things you need to overcome is learning what skills are the best for both the class and your playing style. Now, this can be a bit tough for this class, as you need to know if you prefer PvP or PvE more and you will also need to think about who you will be grouping with the most - such as other massive tanks, other support classes, DPS, and so on.
Normally, I recommend for this class that you try to keep a balance between being a good healer, damage dealer, and support class (or those that can throw out a buff like no one's business). So, to do this, you will have to get your skills in each of the different feat categories. Now, since you're normally going to be playing with other gamers in AoC, you want to make sure that you don't get too many of the defense passive abilities/feats because they won't help you near as much as if you are to get some of the better buffs for your groups. So, you need to stick with the mana passive abilities/feats first, as they will help with the mana regen since this class has a low mana pool, then head on to the heals and buffs that you can use the most on your groups. Once you have these balanced out, start adding in the damage dealing feats and you will find that you'll come out with a well balanced Bear Shaman that is ready for any fight.