I make an activity basket for the next day, each with a daily theme. At the moment we are working on the alphabet, so we focus on a different letter everyday. I have a tracing sheet for her name, the alphabet, and numbers 1-20 that stay in there everyday. And then I try and add as many different activities as I can find relating to that letter. Some of them are more obviously educational than others.
So for letter a I put in there: letter a worksheet, adding up workbook, children's atlas, various animal books, colouring pages of different animals begging with a, craft pieces to make an ant from an egg crate, Spanish book of animals.
Letter b: letter b worksheet, bubble machine, building bricks, blackboard, sound bingo, baby signing, Spanish book of colours, blue crayons and pens, ball, baking and various books.
We have also have a weekly theme bingo. So some of our themes include nature, music, shapes and colours. So my daughter gets to chose the weekly theme, and we cross it off so next week she chooses from the remaining themes. So we do things relating to those as well. We also aim to use different materials where possible too. So one day will be paints, next will be pens,. Next will be chalks, then it may be using yarn. We find aiming for different stuff everyday helps to maintain the interest. And keeping it relaxed without pressuring her to do it, actually encourages her to do it
My daughter doesn't have to do everything from the basket, I pop it on the floor and she rummages through and picks and chooses what she wants to do. Sometimes she will sit and do most of it, even the more obviously educational stuff. Other times she barely looks at it. I wouldn't worry too much about educational stuff, they are always learning stuff from everything around them anyway. Even things like Lego or play dough can be educational. They are learning about building, colours, making shapes, all sorts.
I have a 4 month old so I do find it easier having a basket of stuff ready to go so I can sit with her and play with the baby while she works her way through the stuff. Because it is hard, especially when the older one wants to do everything with you.
I also find rotating her toys keeps her interest in her toys. If she has access to all of them at the same time, I find she tends not to play with them so much.
If my daughter doesn't want to do any of the activities I have made available or play with her toys, I will ask her what she wants to do. If it's a reasonable request and something we can do, we will do it. If she just keeps asking for TV I will suggest a couple of other activities, if she doesn't want to do them and can't think of anything else, I tell her she will just have to be bored then. At that point she usually finds something to entertain herself with.