Eighteen months seems to be the bottle cut off for toddlers. If you still have an infant try to do it sooner rather than later because the older they get , the more attatched to it they get. If your child is nine months or older and you are planning to wean off breast feeding go directly to a cup. These things do take time and I suggest you do not cut your baby off cold turkey for your sake as well as theirs.
You can introduce your baby to the cup as early as six months old and gradually wean them down from the bottle so they are completely off it by nine months old. In my case, which wasn’t a well thought out one, I weaned my eleven month old from breast to bottle. That was a bad decision on my part because he is now eighteen months and completely in love with his ” ba ba”. My current plan that is working well is to only put two ounces of plain water in his bottle when he’s given it. When he’s really thirsty and would rather milk or juice I have it ready in a cup. When we go out shopping I bring his cup with water in it. He doesn’t seem to mind too much when we are on outings but when we are home it’s a different story. He has grown very attached over the months so I know I have a yet another challenge on my hands.
For more information on weaning your child off the bottle please see: