Question: "How can I find my spiritual calling?"
Answer: People want to know how they can find what their spiritual calling is, i.e. what God is calling them to do with their lives. They want to know the one, grand purpose God has for them, the one dominant spiritual gift that will reach hundreds or thousands or millions. The truth is, however, God doesn't call many people to dedicate their lives to one specific area. And if He does, He does so in His own timing.
In popular Christian culture, it is usually the people who find their niche and stay there for years who get the attention. Major para-church leaders, musicians, and evangelists often spend decades working at and perfecting the one area in which God has called them to serve. But the vast majority of believers are not called to a single, ground-breaking ministry. Instead, we're called to several, depending on our stage of life, our spiritual maturity level, and the needs of those around us. God calls us to serve where we are. Someone with the gift of teaching may lead a Sunday school class for a while, teach at a Christian school, and then write curriculum. Or he may work at a bank and find opportunity to teach others about God through more informal situations. We are ultimately called to fill the needs of the body (1 Corinthians 12:7), but that doesn't mean we'll have a single, lifelong ministry to concentrate on, although sometimes it does.
Sometimes, God does give an individual a specific ministry, but He always does so in His own timing. Like training before a competition, it takes time to develop the wisdom and skills we need (1 Corinthians 3:2). If God were to give us the mission before the training, we'd try to do too much too soon. Instead, God holds us back, taking time to build our practical skills (Luke 2:52), spiritual knowledge (2 Peter 3:18), and faith (James 2:22). James spoke to this in James 1:2-4: "Consider it pure joy, my brothers and sisters, whenever you face trials of many kinds, because you know that the testing of your faith produces perseverance. Let perseverance finish its work so that you may be mature and complete, not lacking anything."
Many people are anxious to discover their calling from God, but when "calling" is used in the New Testament, it almost always refers to our calling as believers (Romans 11:29; 1 Corinthians 1:2; Ephesians 1:18, 4:1, 4; 2 Thessalonians 1:11; 2 Timothy 1:9; Hebrews 3:1; 2 Peter 1:10), not our calling to a specific ministry. Ultimately, our "calling" is to love God, love others, obey God, and take care of others. If we concentrate on fulfilling the responsibilities He's given us now, God will take care of our impact on the world.