Share a laugh. Make it a habit to spend time with friends who make you laugh. And then return the favor by sharing funny stories or jokes with those around you.
Knock, knock. Browse through your local bookstore or library's selection of joke books and get a few rib ticklers in your repertoire that you can share with friends.
Know what isn't funny. Don't laugh at the expense of others. Some forms of humor aren't appropriate. Use your best judgment to discern a good joke from a bad, or hurtful, one.