How can we know God’s leading in our lives? What ways does God use to show us how he wants us to serve him?

Firstly, God speaks to us through the Bible. That is not to say God only speaks to us through Scripture. However, everything we believe we have heard from God must be tested by Scripture. Scripture is our benchmark. 

God also speaks to us through his Spirit and through our circumstances.

Sensing God’s direction in our lives can be something sudden; but quite often it is gradual, like the dawning of a new day, or the rising of the full moon above the evening horizon.