If you review a document, it means you read it and examine it (and maybe have some ideas to improve it) - but you don't make any changes.
If you revise a document, it means you change the text to correct errors or make improvements.
When preparing for a test, it's a good idea to study the material again in order to refresh your memory. American English speakers say you are reviewing for the test. British English speakers say you are revising for the test.
If you want to launch an online business, think twice. It may be worth to launch 5 online businesses at the same time and link them in a network. Maybe your flagship idea will consume most of your focus and resources, but having 2 3 satellite websites projects orbiting the main product will have a bigger impact. Not to mention the learning advantage: you will incorporate much more knowledge from a network, than from a single product.