Couchsurfing is a wonderful community, and I would highly recommend them. However, there are some facts you need to be aware of.
First thing you do is join Couchsurfing, and build up a reference base. Few hosts will accept someone who does not have any references. Also get verified as quickly as possible. It is a great assurance to the other party. Two good ways to gather references is by attending Couchsurfing activities in your area, and by offering to host travellers. If you are unable to accommodate any, be available to show them around your area or take them to sights they would like to see. There's nothing like seeing a place through the eyes of a local. Anytime you spend time with another couchsurfer, you are entitled to ask them to write you a reference, just as you would write one for them. The reference system works extremely well, so long as you are honest. If you found something annoying/uncomfortable/offensive about another member, and it was integral to this person, say so. No need to be rude, just be honest and factual. Read through other people''s references, and get the ideas of what works.
It is not just a free night's accommodation. It is a community, and many hosts and hostesses appreciate something in return. I like to take my host out for a meal, at a moderately priced place of their choice. On the other hand, some people who have surfed at my place have brought me gifts, taken me out to lunch, etc. When I take a guest for a drive into the country to a requested site or place, I always appreciate it when they buy me lunch. There are also hosts who prefer that you spend some time with them, and not just use them as a place to sleep. These folk like to meet people from all over the country, all over the world and hear the travel stories.
Some things you might like to offer to do for your host is to cook them a meal, offer to do the dishes, clean the bathroom, or really anything you see you could do. It's all up to you. A bunch of flowers or a box of chocolates on arrival is often appreciated.
Point is, if you have read their profile, and the references, you quickly get some idea of what this person likes. If you correspond with the person beforehand, you can always ask what they would like.
Couchsurfing is a great community, just don't use them a a night's free accommodation. It's a give and take community.
Lifey