Should I prepare my small business return separate from my personal return?

It depends which business entity you are. 

• If you are a sole proprietor, you would file your business income and expenses on Schedule C which is filed with your personal income tax return. You cannot file a separate tax return for the business.
• If you are a single member LLC, you would file your business income and expenses on Schedule C which is filed with your personal income tax return. (unless you elect with the IRS to file as a corporation).
• If you are a partner, you would first file IRS Form 1065, U.S. Return of Partnership Income. The Partnership would issue you a K-1. You would report the K-1 on your personal income tax return.
• If you are a shareholder of a Sub-chapter S Corporation, you would first file Form 1120-S, Income Tax Return for an S Corporation. The S Corporation would issue you a K-1. You would report the K-1 on your personal income tax return.
• If you are a shareholder of a Corporation, you would first file Form 1120, Income Tax Return for a Corporation. The Corporation would issue you a K-1. You would report the K-1 on your personal income tax return.

Related information:

https://ttlc.intuit.com/replies/3301507

I have a startup  small llc should  I be filing with personal taxes?

Thanks