Using costumes and dress-ups and props as a teaching strategy can be loads of fun. Some songs are suited very well for this, especially in Primary. Some of my favorite songs for using dress-ups and props are: "When We're Helping" p. 198 The Children's Songbook, "To Be a Pioneer" p. 218 CSB, and "My Dad" p. 211 CSB. Although the dressing up and holding props provide the "fun" factor, real musical concepts can also be taught.
"When We're Helping" is one of those short catchy songs built around the upper minor third of the major triad. The entire song is sung on only six pitches, well within the hearing and reproducing range of a small child. The words are simple and the rhythms are, too. When combined with simple repetitive actions, this song is easily mastered by even the youngest singers. I like to dress-up the girl child-helper in a frilly apron, a necklace of beads with clip on earrings, and hand her a feather duster. She leads the group as we sing, although we are not limited to just dusting as we act out how we help Mother do the chores. For the Father verse, I dress up a boy in a hat, a pre-tied adult tie, and hand him a tool (usually a plastic replica). We improvise the actions of fixing things using tools - hammering, screwing, sawing, etc. - or working in the garden - raking, mowing, shoveling, etc. We sing as we "work" and we exercise our ears and voices, too.
"To Be a Pioneer" is sung in two parts like a Partner Song. The girls learn the verse and the boys learn the contrasting lower "ostinato" part. Because this song is challenging, I use the donning of costumes as an incentive. When the parts are learned to a point that a few of the children can hold their own, I choose a few to come up to the front and be the leaders of their section - girls in front of the girls and boys in front of the boys. (Sometimes we rearrange the seating for this.) These few children get to wear the Pioneer costumes or pieces of costumes (sunbonnets, straw hats, aprons, vests, etc.) We can repeat in order to review towards mastery and give other children the opportunity to wear the costumes. The repetition reinforces the children's awareness of and ability to sing in HARMONY.
"My Dad" is a fun song to actually use a child as the visual aid. I like to add pieces to his attire as we sing the song. It usually embarrasses him, but it is all in good fun. I have him wear a baseball cap or work gloves or a tie for the first line or I give him something that dad's like to do to hold such as a fishing pole or golf club. I pin an honesty badge on him and hang a picture of a Dad that looks similar to him around his neck. Then I have him do some actions as I prod him along. This song has some big skips in its angular melody - 4ths, 5ths, 6ths and octaves. The children will not know that they are practicing ear training, but you will, and that is a very good thing for singing.
I always have an ulterior motive when using visual aids. That is to teach real musical skills and gospel concepts for each song. The art or costumes or props or actions or activities are just tools to use to do real teaching that can last a lifetime. The object is to help the children learn the song so well that they can sing it without any aid at all. Only then will you know you have done your job!