Be aware of the topics that you like to discuss with advisees and those that you don't. It is human nature to direct the conversation to areas where we are comfortable and to avoid areas that make us uneasy. If there is something that you are uncomfortable talking about, make sure that you connect the advisee with someone that you believe wouldn't mind discussing the issue. Inconvenience yourself for your advisees, and they will do the same for you. If you make an effort to see them in a game, play, or extracurricular enterprise in an otherwise full day for you, they will make an effort to see you.
Clear contracts work.
For example, let your advisees know that if you send a note to see them that it is for a good reason, and it is their responsibility to get in that day if at all possible. Spell out the mutual expectations for the relationship with one another.