Bards are a quite versatile class with multiple ways to play them. Obviously you always want to have one of your concentration buffs or debuffs active and grant some bardic inspiration to your allies. Here are a few suggestions what you can do on top of that:
- Get gear that buffs people when you heal them and then cast heals on them.
- Use short duration debuffs like vicious mockery, dissonant whispers, sleep.
- Deal some damage with spells like shatter or weapon attacks. Hand crossbows can be quite good if you have decent dexterity, especially at low levels when you only have a few spell slots.