Hello,

I have had the same issue with my own conversation class.  For mine, I want to focus on getting their speech better and I focus more on exercises than teaching a lesson or something.  Here are some things we did...

-Basic conversations while 6ft from partner (helps them speak louder and clearer)
-Telephone (to enunciate even when speaking softly)
-Tongue twisters (to help with getting consonant sounds out and fun too!)
-Poetry (to get their words flowing, but tried to keep the poems interesting)

I have just started my conversation classes, so this is all I have done so far. 

Hope it helps  :)