Know the need. Many look at their needs all wrong. Your wants are not your needs. There is no gray area when it comes to your needs. They are solid, tangible opportunities for the miraculous.
Know where to go. So many, so often, look in the wrong places when a need arises. Don't go to the people who are not in need! Go to unsaved friends, people in need, not the friends that are set in their spirituality.
Know the faith. Faith is a pretty exact science. There are literal and tangible things we can do to build or break our faith.