At first i thought that i need to constantly entertain my 3 year old but now I am realising that is wrong approach.
I have now decided I am not a walking video arcade. I have realised that like adults, young children need down time. They're taking in a lot of new information and need some quiet periods every day to process it.
So my advice is that if you and your child are together and she wants to spend some time playing by herself, consider yourself lucky. If she wasn't absolutely sure she could count on you to be there in an emergency, she'd never take her eyes off you. So at least once a day set your toddler up with some Duplo or a puzzle or some other favorite toy and step back.