1. If you're purchasing clothes or shoes online, be careful with all the sizing. Some items typically run smaller or bigger than normal. Some shopping sites will advertise if an item runs true to size. If the site doesn't list anything about sizing, glance at the reviews. In most cases, if an item is running larger or smaller, the reviewers will let you know.
2. Sign up for your chosen online stores' newsletters. Often times online stores sends out daily, weekly or monthly newsletters with special sales, discounts and deals. If you like to save cash, you could possibly score some good deals on items you were going to purchase anyway.
3. Be sure that you're entering your payment details on a safe and secure site. Look for "https://" inside the URL from the site that you're seeking to buy something from. If you don't see that or no symbol of any website security, then it's probably a great idea not to trust those people with your account information.
4. Read customer testimonials before you buy anything. People are more than happy to complain about bad service online, so look for sites and testimonials which are terrible so that you know what you're getting into. You need to take bad reviews having a grain of salt, but if you see many, you know there is a problem.
5. If you are looking at purchasing from the seller the first time, take a moment to carefully examine their past customer reviews. For the most part this provides you with an approximate idea of what sort of goods and services you ought to expect yourself. Anyone who has been rated lowly time and time again needs to be given a large swerve.