If we are going to meet a need, we first must be aware that a need exists. Nehemiah had heard about the shambles that Jerusalem was in, and he went to see the need for himself. There are people in need all around us, we just need to take the time to see them.
Once we see the need that is around us, we need to see our place in meeting that need. God has created you uniquely to serve Him in a very specific way. Are you using what He has gifted you with to evangelize the lost and to disciple other Christians?
Anytime that we decide that we are going to do something for God, opposition will arise. As soon as Nehemiah and the children of Israel decided that is was time to rise up and build, their enemies began to oppose them. You can either give in to the opposition, or build in spite of those that oppose what you are doing.
The opposition to your service of the Lord will be great, but you do not have to face it alone. Nehemiah knew that God had called him to do this work, and that God would be there with him as he led the people in the rebuilding of Jerusalem. God will be with you too! If God has called you to it, then He will help you do what He wants you to do.