Most online stores offer free returns so if the item arrives looking nothing as expected you haven't lost out. You can try it on in flattering light and see if it works with those shoes you bought it to go with. Stores such as asos do most of the hard work for you, their catwalk feature lets you see how the fabric moves and how it fits the model which will give you some idea as to how it will look on you. If even the model doesn't look that great, don't bother! There are also lots of online only stores now such as asos, half of my wardrobe has been bought from them and whilst I used to wish they had some actual stores I am now glad they don't.
I do still pop to the shops, but if there is something specific I want most stores now allow you to check the stock online before you go. This is so, so useful. If you are a store and you don't offer this option yet please, please consider it. There is nothing worse than wanting an item and not being able to find it in store. I do like being able to wander around a store and touch different fabrics as I go but this just isn't a fun experience at the weekend.
The one thing I do miss is the element of surprise. I no longer visit most high street stores hoping to find an undiscovered gem. I check the new arrivals most days so usually know their stock before it has even hit the stores. Guess that's a small price to pay. Are you an online convert like me or do you still prefer the thrill of shopping instore and stumbling across that must have item?