I cut down to about one at night by the time my son turned a year old and then about a week after his birthday I cut that one completly out and he never really noticed since he was used to his sippy cup by that point.

In our house we simply discarded the bottles as they got grimy looking (we have hard water here and its so hard to get off the plastic) and would tell the kids "sorry no bottles right now" and they'd take the sippy then because they were thirsty enough to not care how they got thier drink. We don't have any more bottles here and only 1 or 2 at the grandparents so the girls aren't picky about them anymore.

If that doesn't work you could try a couple of distraction tactics. Like Bottle fairy needing bottles for another kid or maybe 'plant' the bottles in the backyard and in the morning 'wow! they turned into a tree or flower or something'... make something up. Then get him a special sippy cup or something to commemorate how he's such a big boy.

i am doing this slowly for a few reasons...my first son i just completely took the bottle away and dealt with a week of tantrums and not sleeping...but he wont drink milk. six years old and has never had a glass of milk. so with this one, i weaned him from formula over a three week period, each week decreasing the amount of formula while uping the amount of milk. this worked great. now we are only on milk and now i am decreasing the amount of milk. he used to have a 6 oz bottle now it's 4. i have taken that down more slowing doing it for two weeks at a time. next week 2 oz. so far total luck with this and he will drink from a sippy. i am not fond of kiddos going to bed with a sippy cup, but that is a personal choice. as by the time he is 18months the goal is that he is going to bed on his own...and then that will work for the toddler bed.

hugs.
for those who are super attached to it, just taking it away works. it is hard, but its just a week of hell vs years of bad teeth and habits.

(i have taught preschool for 12 years and weaned many kiddos)

For me i just take it away at 12mos. I make it causual and I have had no issues with this. My oldest I did not do this and he was harder. he had it at night till 19mos but my girls completely off bottle at 12mos.

For me I started introducing a sippy cup for some of his meals. Once he was comfy with it I just stopped giving him the bottle. It was a pretty easy transition and he didn't seem to miss the bottle at all.