Perhaps the children have certain favorite songs they like to sing. Great! But does the teaching of the song correlate to the teaching of the Bible lesson? How about the memory verse?
The main truth taught during the Bible lesson should be brought out in as many of the activities of the day as possible. Try not to “overteach” by bringing out a different lesson to be learned by each component of your agenda. Teaching only one truth is plenty for one day for most children. So teach it thoroughly. Bring it out at least several times during the Bible lesson, choose a memory verse that teaches the same lesson, make it the main truth of missions time and prayer time.
For more on developing a main truth, see the tips for 6/17/96 - Two Kinds of Students and 9/1/97 - Food For Growing Children.