Re: I want to get serious about weaning
I would plan a few days to a week during which you are very busy and rarely at home during the hours when you want to cut down on her nursing--go to the park a lot, do lots of play dates, do lots of exciting and wonderful things. That will be more likely to distract her and it may help to get her out of the habit of nursing during those hours.
Then you can do the "don't sit down" method thereafter--don't sit down during the hours when you don't want her to nurse, particularly in the spots where you usually nurse her, if you have some favorite nursing chairs.
I would just start with a few hours in the morning or afternoon, and when she's into a pattern of less nursing during those times, try adding more times of reduced nursing. It will be a long process, but I think it will be gentler on you and her overall.
Catherine, tandem nursing mama to Preschooler Girl 9/08 and Toddler Boy 3/11
Breastfeeding for 4 years and counting!