1. [..............]  
Try to find a physical address somewhere on the site, and some information about the company. A reputable business will want to tell you about itself. Look for phone numbers, and if you can't find one, email and ask for these details.

2. [..............]  
See how long it has been established (go to http://www.archive.org/web/web.php). Put the business's name into a search engine and see if anyone has complained about it. Start with a small purchase and see what happens. Remember if the site is in the EU is is legally bound by the distance Selling directive.

3. [..............]  
Make sure that the goods are clearly described, and that all charges, including delivery and tax are listed as part of the total. Remember that some purchases, such as with a credit card offer more protection.

4. [..............] 
Make sure that your merchant has the goods in stock - and won't charge your account before they arrive at your home. Check delivery times, and check how the goods will be delivered. Courier is faster (but more expensive) than the mail.

5. [..............] 
The merchant should have a policy displayed on the site telling you what information is being asked for and why. There should be an explanation of why it is needed and how long it will be kept for. It should also say who that information will be given to.

6. [..............] 
Goods might not arrive, be damaged, or not be what you were expecting. What happens next depends on where you live. But in every case, you should go first to the company, and explain what has gone wrong. Often a polite description of what has gone wrong is all you will need. If not you may need legal advice.