A group of troubadours isn't called a party, it's called a band.
The troubadour is a neutral bard that enjoys playing rousing music for their party, increasing their ability to fight against the monstrous denizens of Norrath and recover from the wearying effects of battle. Their songs are infused with powerful magic, inspiring the troubadour's companions to perform incredible deeds. For players who want to play a very active support class with a wide variety of abilities, the troubadour is an excellent class for you. They spend very little time actually mixing it up with monsters, instead focusing on making it so that the party specialists can perform their activities at peak efficiency.
This class really shines only in a party. While they can solo, it's really not the best use for the class - if you're looking for one that can, it'd be wise to pick another scout class that can do more damage. Most of the troubadour's abilities are focused on buffing other classes to make them better at what they do. The troubadour's spells can be broken up into several categories: songs that regenerate health and power, those that increase statistics, melee attack speed and finally those that cause mental damage to enemies periodically. Most songs act like a constant pulse, giving their effects only so long as the bard in question is playing the tune.
Agility is an important statistic for giving them more avoidance, while intelligence gives them more mana with which to use their songs and other abilities with. They also often use bows, sometimes enhanced with poison arrows, to increase their damage output. When choosing your songs for a particular battle, it's good to determine your group makeup. Which classes are doing the most damage? Do you have more melee characters than you have casters? Are there any particular problems that this group is having that you could help with? For example, if the healers are having trouble keeping up with incoming damage, a regenerating health song might be appropriate. If your casters keep running out of mana before the fight is over, a power regeneration song would be very helpful. In addition, you need to be able to cast your debuffs and direct damage spells when appropriate to get the most out of your character. There's a lot for a troubadour to keep track of!
Troubadors also have access to interesting spells like a charm that enables them to take control of an enemy creature. It's also improtant for a good troubadour to use their threat reduction spells and songs on the casters and damage dealers in the group to assist with crowd control.