You should read the person's entire profile and read through their references. References can give you an idea of what others think about the person. It is also very important to communicate thoroughly with the person before accepting their request. Be sure to ask for any information that is missing from their profile or request message. For example, if their profile is empty or missing a photo, it is okay to ask them to fill out their profile and/or upload a photo before accepting their request.
It is also good to ask the person when they will arrive and when they will leave, why they are coming, and who is coming with them. It is helpful to let them know what your schedule looks like and how available you will be to interact with them. Don't feel obligated to provide a bunch of details or private information, but you should let your guest(s) know about any important information about you, your home, who lives with you (including pets!), and your schedule that may be relevant to their visit.
Keep communication on the Couchers.org platform as much as possible. Use common sense when reviewing requests and profiles and especially when providing personal information like your address and schedule. Keep in mind that you are never obligated to accept a request or provide a reason for why you cannot accept. If you decline a request, the person will not be able to message you again unless they visit your profile and send a separate message. If you accept a request but change your mind, you can reject a request up until the start date of the request by clicking the "reject" button at the bottom of the request.