If you’re going to have merely milliseconds to capture expressions, and maybe a little longer for poses, you need to look to fast lenses and high shutter speeds to help you out. You also need to work quickly, so complete familiarity with whatever gear you’re using is vital. The worst thing in the world is an amazing moment happening, and you’re at the wrong setting or just not ready.
Two words: be present. In a society that spends so much time on the Internet, I truly feel there’s no substitute for personal contact—whether with clients, prospects or industry peers. Get out and meet with people. Second, look the part. Dressing professionally really does matter in an industry based on impressions.