Those of us leading worship in a congregation is not unfamiliar with 'the 20 minutes'. In this time frame it's Your responsibility to "wake people up", making them sing, making them feel comfortable and most importantly: Making them worship. It's hard to measure wether people worship or not. It's often a subject to personal worship styles, and that woman on third row with her eyes closed isn't necessarily less of a worshiper than that guy on the first row with his hands in the air. For me giving people space has been a key word for leading worship. It's our responsibility as worship leaders to create the necessary room for people to worship. Maybe you can move away from the microphone once in a while, making people listen to their own voice. It will surely effect how loud they sing. Remember that the music never stops. Try to keep at least one instrument playing. Avoid the long pauses between the songs, where you look desperately through you papers, looking for the lyrics to the next song. Be prepared, and prepare in advance some songs who go well together, so You can bridge the songs.