A good posture, focusing on the moment, the sensations, the breathing, accepting the thoughts but not feeding them. Do that every day and be patient. It is best to practice with other people as more experienced people can guide you. Some people start right away with a retreat. It is also a good way to start.

I... need a guide or something. I expect I'll do more research this weekend, but just sitting and listening to myself breathe? I have plenty of calmness in my life, but surely there's a difference between meditation and relaxation?

Sorry, not really directing this at you, its late, kinda just stream of consciousing before sleep. I do appreciate your response : )

Check out https://www.headspace.com/ They have guided meditation that I really like. At least give the 10 free days a shot and see what you think, nothing to lose!