One of the best ways to start is simply to begin with prayer and Bible Study on the subject of missions in the Bible. Initiate a missions prayer focus, once a month. Supply information for a special prayer for missions or missionaries in your Sunday School class, Adult Bible Fellowship, small group, or wherever you are active in meeting with other believers.
You might want to launch an elective class or meeting focused on missions. There are lots of resources, DVDs, books, etc., around which you could form a study group to talk and pray about missions issues. Read more articles on the Propempo.com website and get or download the many resources cited/recommended.
Take your friends along to hear a missionary speaker or attend a missions conference.
Give simple, well-done materials to your friends to encourage and inform them in missions.
Invite a missionary to give a presentation at your home to a group of your friends and acquaintances.