What else besides filing quarterly taxes should I be doing as an independent contractor?

[Bsch4477]

This might help. 

https://www.irs.gov/businesses/small-businesses-self-employed/self-employed-individuals-tax-center

[JandKit]

To operate a business that is IRS proofed, As an independent contractor filing quarterly taxes are very important. In addition to the filing of taxes is the need to keep very good records for your business. You can do this by Retaining and documenting ALL INCOME that you receive in the course of your business. Further, All of your EXPENSES should be documented as well.  Written in a legible format that can be used to verify any and all expenditures.

These records should be backed up by the original receipts for any items purchased or income received during the course of the year.