I'd say the first step is definitely to just call and make an appointment. Go to coffee or lunch, let it be casual.If you happen to be meeting a bride at a venue, show up early and make arrangements to meet with the coordinator first- that way you can introduce yourself. Just make sure you're always dropping in to show your face so you establish that relationship. This is actually something I need to get better at too, because even if you have a relationship, if you find you haven't worked with a vendor in a while it can sometimes lead to Out of Sight, Out of Mind.