Deep tissue massage is also a must, making sure the therapist is getting deep enough to hit the hamstring origins - not easy to do!
Agreed on the massage. My LMT was surprised I let her get that deep. It's kind of a precarious spot! But it definitely helped early on. I haven't gotten one recently.
Right now I am seeing a PT once a week. He is having me do hamstring rolls on a stability ball, 4-way hip using a theraband, downward-facing leg lifts, and "walking" while sitting on a rolling chair (fairly tiring). Also, stretching the hamstrings and hips/glutes a lot. He does ultrasound every session too. At home I do a lot of core work, along with the theraband, ball, and stretching activities.