I didn't find TV much use for doing stuff when DS was younger (pre-2 or 2 1/2) because he could only sit still for maybe one 10 minute programme, but then I found that things like Room on the Broom or Gruffalo that are about half an hour were OK, which is actually a useful length of time. So generally I'll say "we're going to watch X and then we're going to turn the telly off" and then remind him near the end of the programme. He won't always manage to watch for longer than that even now (he's 3 and 3 months), and will (sorry!) sometimes tell me he's finished watching and wants to do something else.
One day a week we are mainly home and I am trying to get stuff done and I also have a DD 11 months so this is what we do that day, more or less.
We usually manage to have a bit of a lazy start and we sit and read some books together while DD has her breakfast bottle but he and I have finished breakfast. Then I say I'm going to tidy up breakfast and if he hasn't already grabbed some cars to play with I suggest either Lego or his tractor/barn (Little People). I just give him a choice of two. I'd probably take DD into the kitchen at that point though now she can crawl she usually goes and tries to nick his toys.
She goes down for a nap and we either do a quick puzzle or maybe another book while she settles but then I show him how to do a game on the "Ah-pad" and I can get on with something then for maybe 20-30 mins.
We have a swimming lesson late morning and he still naps after that so then he'd wake up early afternoon and if DD is still asleep I do either playdough or painting or maybe some baking with him, it's hard when she's up to do those, but it never takes that long to do those.
I try and leave watching TV till I REALLY need to get on with tea or something so then I'd say we'll go and play Lego together, but usually he is fine with me watching and commenting and him playing which means I can then gradually retreat and again see to DD/get on with other stuff.
I almost always say "we'll watch telly after X" rather than "no telly now" and that trick seems to work with him.
He also knows the routine on that day so will ask for books after breakfast, and Ipad later that morning, for example.