Get to know individual missionaries personally. This would include receiving their newsletters, praying for them, and financially supporting their ministries.
Consider a Mission Training International workshop on language acquisition and entering a new culture, even for your children!
Find out what options to go are available to you—denominational mission structure, your local church (by itself or with a partner mission agency), or through an interdenominational mission agency. Ask your pastor what mission agencies are already connected to your local church.
Seek some general counsel at the Mission Agencies section of Ask a Missionary.