1. A reputable online seller should have a history that is recorded with the Better Business Bureau. Check with the BBB before you decide to part with your hard earned money to see if there have been any major or continual complaints lodged against them. You don't wish to be spending your money using a company that fails to provide.
2. Ensure that you're entering your payment details on a safe and secure site. Search for "https://" inside the URL of the site that you're seeking to buy something from. If you don't see that or no indication of any website security, then it's probably a great idea not to trust those people with your account information.
3. Make sure to read all the information about any product you are considering purchasing. Just looking in a picture online can be deceiving sometimes. It will make a product look bigger or smaller than. Make sure to look at the description which means you know exactly what you really are purchasing.
4. Although it may look tedious, be sure you read the contract and terms before you purchase at a website. These documents have valuable information about what you can and cannot do when you have an issue with the item that you bought. Read them thoroughly so that you do not have an unwelcome surprise when trying to return items.
5. If you have questions while shopping, choose a live chat function on the online store. Many big brands (and even some boutique stores) now have this functionality. You can chat immediately with a customer support representative to repair any issues or answer any questions before buying. That can present you with a lot of reassurance.