1. Make sure to read all the information about any product you are considering purchasing. Just looking at a picture online can be deceiving sometimes. It can make a product look bigger or smaller than it is. Make sure to look at the description which means you know exactly what you really are purchasing.
2. Make it a habit to register for price alerts. This goes even for purchases that you've recently made. Price alerts will let you know when a product has dropped to a price you like. And when you've recently purchased at full price, you can request a price adjustment to meet the new deal.
3. For those who have questions while shopping, search for a live chat function around the online store. Many big brands (and even some boutique stores) now have this functionality. It is possible to chat immediately with a customer care representative to fix any issues or answer any questions prior to buying. That can give you a lot of reassurance.
4. Be careful in regards to the online stores that you consider buying from. If the online store is poorly designed, full of misspellings, and overall fishy, you should take your money elsewhere. These are signs that something might not be right about this store. It's better to be safe than sorry.
5. If you're considering buying a product online, check out the reviews. The reviews using their company people that have used the product should be able to give you a wise decision about the product. You could possibly find out the quality of the product, when it worked as described, and if you should make the purchase.