I sing in a sea chanty group. There are 6 of us. We do a number of slow, beautiful chanties as well as plenty of high energy chanties. We find it helps to vary the lead singers.

In our group we use a lead singer with the rest of the group chiming in on the choruses (chori?) and refrain lines. In a single evening's performance you will hear every member of the group at least once and sometimes three or four times depending on the length of the set.

Also we break up the group into smaller groups and solo performers so the audience isn't continually bombarded with the "full Russian chorus" (this is a phrase we use about aourselves) throughout the set.

And we include, if we have time in an evening, poems and stories. And we have a pretty good patter between songs that keeps the audience educated, amused, and awake. Plus you should see our low tech special effects.

Here are a few tricks I learned in community theater. To keep the fresh edge in your voice do a few light exercises just before you go on stage. Try a few jumping jacks or push hard against a wall. Then push away from the wall and step out in front of the audience. That little bit will give you an energy that the audience can pick up and reflect back at you. done right that energy will bounce between you and the audience all night long.

Most importantly make sure the audience can see that you are out there having fun.

I think that is more than you asked for but it all contributes to keeping the slow beautiful songs bright and new.