I learned a new strategy about asking questions from the article The Right Way To Ask Questions in the Classroom by Ben Johnson. He states that we ask questions to make sure our students understand the material, but we need to be careful because only the "smart" or "confident" children will answer and the other children would not be even pay attention to the answers.
Johnson states that we should ask the question, wait a few seconds and then pick a random student. While I know some students would think this in unfair or mean, I think it would be effective. If you did this on a regular basis as a teacher, it would make your students actually listen to what you are teaching in order to be able to answer your question if they are picked at random.
Another strategy I like to use is to ask the children their opinion on the subject. It helps me get a good idea if they are absorbing the information and it gives me ideas on how to teach it by hearing it in their own words.