Upvote:6
Forget about Schengen for a few years. A rapid second application will just get you a second refusal.
In a comment you mentioned that your travel history consists of one visit to Dubai. You are very unlikely to get a Schengen visa (or a US visa, or the UK, or any other comparable destination) without being able to show a much better record of having travelled outside of and returned to your country.
In the meantime, keep paperwork for every major aspect of your life, including regular financial support for your sister and invoices/receipts for ad hoc expenses. You might also consider incorporating your sole proprietorship into a Private Limited company, as has been suggested in several comments.