Hi Casey,
Like I mentioned in our birth club, when I taught music to LO's -aged 2 yrs old, our lesson plans were based on their attention span being 30 sec at a time. So we introduced an activity in 15 sec had the LO's repeat for 15 sec and then to reinforce the activity we added another prop or instrument for another 30 sec. to build the lesson plan.
So when you offer her her sand box for example, let her play as she likes, then once she is fed up and maybe comes to you, offer a new item like a rake or some toy bugs etc...then leave her to it again, then she'll play, she'll bore, she'll come to you, again now offer something even more exciting like a bucket of water to play in the sand, again leave her to it. Whilst she is doing that, set up something on the sidelines that I like to call an obstacle course. So I would put nearby my DS for example his wheelbarrow and big shovel and soem stones and I also would add close by as well a bucket from my laundry room and fill with baby shampoo soapy water and a cloth. I would just leave the obstacle course items there and see what he takes to. So let's say he approached the bucket of soapy water, I would let him have a splash and mess around and just be going about my biz like weeding or hanging out laundry and just say things, like "Wow, you clean the bugs? Or should you go and clean the wheelbarrow with the cloth?" Assigning tasks is amazing at this age, they are task masters. After some time of own playtime, I would invite him to come over and join me and help me with whatever I was doing to make the playtime come to an end by finishing with some 'Mummy and Me' time. This type of play should be encouraged and practiced throughout the day and repeated as well so it becomes a mini routine for her KWIM? Some little ones need to learn how to play on their own, like some need to be taught to go to sleep on their own. So, it is important that you are there parallel playing/working with her, but still engaging, organising, setting up an activity and building it beyond and also assigning tasks. This will build up her confidence, creativity and her comfort level with playtime alone but still have Mum time too.
I have loads more ideas, but speaking of laundry, it calls, Nello is napping.
I can come back though and hopefully other Mum's will share too. I just try to approach parenting like teaching and I love to teach playing, so this comes very naturally for me as I am a big kid who loves mess, likes to keep busy and enjoys tasks too!
HTH,
Aisling x