The ABC's Of Building A New eBusiness "By failing to prepare, you are preparing to fail." Benjamin Franklin (1706-1790)
Find a niche market that you have some experience or interest in. You will be more motivated to research, create and market a web site and determine optimum promotional strategy if you have a 'passion' for subject.
For instance, say you are a musician or have interest in musical instruments, Next, you need to scope out demand and competition on internet. You can find this out in many ways, one is to go to http//www.altavista.com or http//www.google.com and do a search which will give you number of pages of competition listed. As of this date, 'musical instruments turned up 2,460,000 web sites! But 'used musical instruments' only 848,000.
As far as demand, go to http//www.overture.com and do a search for number of times musical instruments (68,294 searches) or used musical instruments (2,094 searches) was requested. Much more demand for more general term, 'musical instruments than 'used musical instruments' but also much more competition. You might even want to reduce your keyword phrases to more of a 'niche' market, such as Homemade musical instruments or discount musical instrument.
Now that you have decided on product(s) you want to sell online, you need to establish a web site and/or ezine/newsletter. Decide on a domain name. This is a very important task as search engines place some importance on name relating to what sites theme is. You can do a search to determine whether your chosen name is available at most domain name registrar sites. They call it a whois search. You will need a web host, one I recommend is Host4Profit, http//www.roibot.com/w.cgi?R38406_host but there are many web hosts available. Make sure you get features you need such as bandwidth, POP email accounts, autoresponders, and total capacity.
You can do a whois search, register your domain name and start building a web site immediately. Host4Profit also offer some instant businesses you can start selling when you sign up. It is affordable and their services are excellent.