In order to succeed in student retention students need to know you care. We've all heard the saying that goes something like "they don't care what you know until they know that you care". Once they know I have their success in mind, then we've started the process of building a firm foundation for success in the course. Also, struggling students often are scared to ask questions so it's important to be open in class and encourage everyone to ask questions regardless of how silly they feel the question might be.