How to Shop for Clothes and Shoes Online
Measurements, not size. I wear a size 2...or an 8. The measurements are the only numbers that matter. If a website doesn't have measurements posted, some will provide them if you contact customer service. If a website only provides clothing sizes, I am unlikely to buy.
Cut matters. My hips tend to trip me up the most when buying clothes; pants and shorts aren't high on my list of things to purchase online. But I know that as long as the waist and length work, I can buy any full skirt. Likewise, I know how different toe shapes will fit my feet, making me more willing to buy a round toe than a pointy toe online.
Material matters. I will buy cotton, linen, silk, and jersey online because I have a good idea what the fabric will feel like. Woven polyesters, however, could feel soft or plasticy. Wool could be soft or itchy. Spend some time getting to know fabric so you can minimize any surprises.
Trust in brands. If you know a certain brand fits you well, you should be able to shop that brand online with little issue. If you are uncertain, try to find somewhere in your area that carries that brand. Even though the store doesn't have the item you want, you can still learn about how the label cuts it's clothes or shoes.
Read all the reviews with a grain of salt. Certainly read the reviews. How do people say the item fit? Was the fabric thin and sheer? Did reviewer after reviewer complain about poor workmanship? This will give you come idea of what to expect; however, not all reviewers are created equal. A dress I was looking at had a very low rating, but this was because several reviewers who each happened to have a DD cup or larger had complained that there was not enough room in the chest. Some people pay $20 for something and then complain about how cheap it was made/looked/felt. Amazon users can be particularly bad, posting negative reviews about a product when their issue is really about a seller they do not identify.
Check the return policy. If you have to pay for return shipping or they only offer exchanges, maybe shop somewhere else. (Note, not everything on Amazon is being sold by Amazon. Amazon has free shipping on returns but not all of their sellers do.)
Be patient and plan. Not everyone is Amazon. Shipping in the US can take up to six weeks, and not every shop has a top of the line shipping system. Sometimes it's just a couple people doing all the picking and packing. Know where the company is shipping from so you have better expectation of shipping times. If you want your package faster, spring for better shipping. Don't order something a week before you need it then freak out on customer service when it arrives.
For those of you worried about security, have a credit card that you only use for online purchases. Do not use your debit card online. Yes, this is extra bit of paperwork, but in case the website is hacked it will diminish your damage. (Smaller retailers don't actually have your credit card information. They let the processor handle all of that.)