Have a decent amount of experience building relationships with this demo. I've found face to face, if possible, brings the best results. Decision makers are often hard to get ahold of and, unless you are face to face when you finally connect, you are not likely to have their full attention / interest.
Online, most of the big venues have a facebook profile and someone on staff who manages social media... engaging that way, with a personal approach (vs blasting a form email) would be the next option. For restaurants, you may have to fall back to a website + email.
In both cases, focus on what's in it for them to hold their attention.