Know
First, being a Christian means that you know Christ as your saviour. Not just an acknowledgment that He existed, but having the Peace of Christ in your heart that surpasses all understanding. It is knowing that he died on the cross for you, and that you will be in eternity with Him.
Grow
Each Christian must grow in their faith and in their knowledge of Christ. This is done by reading and studying the Bible, God's perfect word to us; by attending worship services, hearing the word and singing praises to Him; thru fellowship with other believers, thru prayer, our direct contact with our gracious God; and by living a life worthy of our calling, being obedient to Christ.
Go
The natural working out of our salvation is by serving our Great God. What a wonderful privilege we have to be part of God’s plan for his creation. Some see this as a calling to evangelism, a call to service or even both. In any event, Christ has called us to be effective in our lives as Christians. See the article on Salt and Light.