I guess we started gradually weaning at 6 months, just when Sophie was starting to eat solids - cutting down on nursing was more like a by-product of her starting to eat solids is maybe more accurate. I continued to nurse on demand, but fed her regular foods as well. First at times when she was hungry (a couple of times a day), but slowly moved toward having solids more regularly.
At 9 months I went back to work and my husband took over. A couple of weeks prior to me returning, I started more seriously with the weaning so that she was able to go without nursing for a full day (I gradually cut back on nursing sessions, shortening nursing sessions and that kind of thing while replacing nursing with solids). In the end, I nursed in the morning before leaving for work and then on demand when I returned. Often that meant that she was mainly on the boob at night, but during the day she was drinking water and eating solids. On weekends, she continued to eat solids, but I nursed on demand. My midwife had recommended to do that since it would help keep up the milk supply during the week.
We totally weaned when she was about 14 months old. Again, we did it gradually, probably taking an entire month. We cut out on demand weekends first, but I continued the morning and evening on demand nursing. Then we started to gradually shorten each nursing session - rather than letting her go for as long as she wanted, we cut her off after x minutes, reducing the minutes slowly. Then we cut out on demand nursing on evenings, so she was left with a morning and an evening nursing session. We shortened the morning and then cut that out completely and after a few days of her nursing only in the evenings for a few minutes on each side, we cut that out as well.
The first day of her not being allowed on the boob was a bit tough. She didn't cry much or anything, but she just tried her best to come close and was pawing at me. She was okay though when offered solids, but all day long kept up the pawing at me. The second day, she already knew. She made a half-hearted attempt to get at the boob first thing in the morning, but didn't complain when I told her no.
We never gave her formula or a bottle, just had her sip water. First out of a real glass (she refused the sippy cup), but once she was done with nursing completely, she pretty quickly started liking the sippy cup. That's also when we started her on cow's milk - which she didn't take at all for a few weeks, but now she is heavily into it. So much so, that sometimes we tell or no or else she won't eat.
Good luck to you. I remember it was a big step to stop nursing....