Grace had colic... and honestly, I tried everything. Some things helped.... I was breastfeeding and went off of dairy which helped her tummy. We also tried meds for reflux. That didn't help so much (or at least I didn't notice any huge change). Infant massage class helped. Lots of time being held. A nice warm bath always calmed her, so I gave her one 3 times a day on the worst days. She liked the swing... being upright in it and the swaying motion made her calm... she took naps there on her very fussy days. She was swaddled at night.
My best advice for her is to hang in there and don't get angry at the baby, it is really hard to stay calm when you have a baby that cries for 3 hours straight.
Grace seemed to just magically grow out of it at 3 months.