I have four kids, but I still struggle to get my children to study on their own despite to all my experience!
First of all, we have to recognize that all kids are different, some of them will study on their own, but the majority needs attention from the parents (and enforced discipline).
Second, there is no short answer to the question, how to make a child study on her own. The parent will need to honestly understand the mindset of his/her child and try to adapt to his/her learning habits.
I would advise reading the below articles which are relevant to the asked question:
How to Stop Your Child from Procrastination During Studies?
How to Increase Attention Span and Concentration among Kids?
But in overall, my suggestion will be:
- Spend the time studying together with your child
- Enforce the discipline for regular studies at home