I want to open an online clothing business (in Illinois). What sort of legal procedures must occur first?

It will just be operated by myself. Do I need to register with the state for taxes? Also, do I need to file anything else with the state before I begin? Thanks!

The state of Illinois has a business portal that has everything you need for starting a business http://business.illinois.gov/starting.cf...

If you are planning to start as a sole proprietor, then the legal requirements are simplier.

Start by registering your business. Go to your county clerk and request for information on business registration. Here is a list of county clerks in IL - see if your county has a website and whether they do business registrations online
http://www.elections.state.il.us/Electio...

Since you will be buying and selling products wholesale or retail, , you must register with the IDOR. To obtain information contact:

Illinois Department of Revenue
Central Registration Division
PO Box 19030
Springfield, Illinois 62794-9030
1-800-732-8866
TDD: 1-800-544-5304
http://www.revenue.state.il.us/Businesse...

Typically online businesses are not required to be licensed nor required to get permit to operate (it's different though if you will open your physical clothing store); but nonetheless double check with Division of Professional Regulation http://www.idfpr.com/dpr/default.asp

Here is helpful guide to all things legal if you want to take the route of filing online. Depending on the size of the business and where you will be selling with determine your filing.

For Legal Tools: www.nomorecubes.com/business-legal-tools...

For information on setting up an online web store:
www.nomorecubes.com/websites/