Hi J.,
I have something that worked for us. Make "Tv Tickets" (Something visual and she can have like her own money) Decide how much time you will allow her, write it on her "TV Ticket". This can work a couple ways for you, not only will it help to reinforce her number recognition, and counting, but will also help her learn time and budgeting, and you could also use extra 5 minute-30 minute tv tickets as incentives for behaving or doing chores. You can also take tickets away for misbehaving, not listening, throwing a tantrum, ect. Tv tickets can carry over if you want, so if she does not watch tv one day because there is a movie or something she doesn't want to miss later that week then she will have enough time. You can really work them however you want. maybe even get her a special wallet or purse to keep her tickets, kids love to pretend they have money or pay for things and it might help get her excited about it.
When she wants to use her tickets, I would suggest starting her time at the hour or 1/2 hour, so she can catch a show from beginning to end. There is nothing like a tantrum from a child who was in the middle of their favorite show only to have it turned off midway through!!
I would also suggest to have books or activities for her when it is not tv time, such as... books, sidewalk chalk, coloring books & crayons, a sand/water table or sand box (outside for the sand things of course!!!) or even cleaning supplies that are her sized, like a kid vacuum, broom, dust pan and mop. You can either have it quiet and chat together or let her pick what music to listen to. Things you know will work for her, keeping her occupied and not thinking about tv.
You can even have Field Trip Adventure Days.. anywhere can work. The park, the Mall, local fire or police department, library ect. Just for a change of pace, and get her out and about and seeing new things.
Anyway, this is what we did, it worked for us. Good Luck & have fun! :)
-T.