Be clear with your requirements (children, pets, facilities, etc.) but be polite in your explanations.
Photos are a MUST, especially in today’s digital age. What cannot be explained is seen. Don’t be shy showing the ocean view or the quaint look of your street, or the city scene from your terrace.
Send out messages right away to everyone who fits the bill. Start with the people who have indicated a preference for your destination and dates. If you don't receive a positive reply, expand your target to include those people that have indicated they are open.
Communication is the key
Once you get a positive answer from a prospective exchanger, you have to communicate with each other often. Ask a lot of questions. Decide whether you were made for each other.
Never presume the other person is like you or have the same needs as you. Discuss nitty-gritty things like allergies, handling utilities, appliances, cooking, and other worldly matters as payments of utility bills, phone calls, and Internet use. Agree on a policy on who will pay damages for accidents, perhaps, including insurance coverage on things.
Of course, a good match is someone with your similar interests. If you have children, a family with children is best. Retired people adjust best with other retirees.
Once you had linked up with a suitable partner, it is best to continue your communications. If you have communicated often enough and are open to one another, by the time you arrive at the other person's home, you are not strangers anymore.
If everything had been set and agreed upon, send an e-mail asking for a confirmation of what is agreed.
Most experienced exchangers swear they never use one, but it is good policy to put in writing what was agreed upon. People forget. Written records stay. This can include who is liable in case of accidents, who pays any insurance deductibles, arrival and departure dates, number of persons swapping, how to handle a trip cancellation, and so forth.
This list is by far incomplete because other details such as preparing your own house for your guests, or how to pack up for your trip to the other house are not included.
But the most important part had been done and you are on your way to a wonderful vacation. What’s more, you know your home exchange partner is going to have the same. What could be more perfect?