M.K.
My daycare lady went directly to an open cup with DD, so that's what we did at home too. We used those really small dixie cups (like 3oz) with only a bit of water in it. She had the hang of it within a week or so and could also drink out of a regular water bottle (with some help) on the go. Introduced the cup at one year (while still giving bottles for milk) and did away with the bottle about 6 months later. It was pretty smooth transition.