Your online small business opportunity begins with a domain name and the domain name you choose is very important for your online small business.

"Choose a good domain name"

Choose a domain name ,hopefully your business name is available but if not try variations like "yourbusinessnameonline.com" but avoid using dashes or numbers like "my-business4you.net". The shorter the better (most people don't like typing long names plus it increases the chance they will misspell the name! Get a top level domain (TLD) name if possible the two best are .com and .net ,they are used a lot and by people.
Use what are known as "keywords" in your domain name. If you sell wood carvings for example, you might want to use "uniquewoodcarvings.com" because then we can title your page Unique Wood Carvings .com and throughout the website use those words to describe various carvings. Search engines look to see if the content of your website matches your title and description.
Avoid using names that might infringe on copyrights or trademarks.This could lead to lawsuits later down the road.
Have fun with this process , once you find that perfect name we can register it for you very fast and it is yours to keep as long as you want it.