1. If you're purchasing clothes or shoes online, be careful using the sizing. Some items typically run smaller or larger 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 the item is running larger or smaller, the reviewers will let you know.
2. Do not forget to comparison shop when you are looking for things online. People usually do that when shopping in physical stores, but they don't think about it on the web. If you go for the first sale you see, there is a chance you are going to miss out on a much better deal somewhere else.
3. For those who 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 service representative to repair any issues or answer any questions before you purchase. That can provide you with a lot of peace of mind.
4. Sign up for your favorite online stores' newsletters. Many 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 great deals on items you were going to purchase anyway.
5. Read customer testimonials before you buy anything. People are delighted to complain about bad service online, so search for sites and testimonials that are terrible so that you know what you're getting into. You ought to take bad reviews using a grain of salt, but if you see many, you know there exists a problem.