Here is a small list of Do's and Dont's when setting up your small business. This is by no means a comprehensive list and you'll want to be adding to this list as you learn more however this is a great place to start.
"Do's & Don't-s" - just a few each.

DO set up your business properly. That is legally with all the right licenses, taxes and fees.

DO set up the correct business structure for your business to obtain proper business tax advantages and lower personal liability.

DO be professional in your business and make sure your "no" means "no" and your "yes" means "yes." 

DON'T operate without liability insurance. Cold hard fact one out of every four businesses get sued. Protect your proverbial assets.

DON'T forget dogs bite. Think about it...Say you have a dog walking business...The dogs may bite you and they may bite strangers when you walk them. Who is ultimately at fault here? Make sure that is in your contractual agreement.

DON'T hire friends to cover for you unless they are ...

Where do you start when setting up a small business? What is the order or process you should go through? Should you write a business plan or is there something else you can do? Ed R shares his take on these questions and gives some tips to help you out.
You can usually start at the end and work your way backwards - writing down every step in reverse until you get to today. Sounds sort of like a the "Monty Python School of Business."

Let's take a hot dog stand --> I want to sell hot dogs at the fair. I am going to need a stand. Do I buy, rent, build one? I will need a health inspection of that stand - that has to happen after I buy, rent or build. I will need a food vendors license - I can buy that just about anytime. etc. etc. Until you end up with what you just thought up of doing - I want to sell hot dogs at the fair. You just reversed engineered your whole business plan.

At any given time in that process you may stop and access the costs to insure you will remain profitable. The bu...