Visualization: An Open Source Question

Over the Christmas break I have been laying out how I want to spend my time in terms of chess training.  As an armature player with a family, ad day job and other things going on, I only have so much time.  I am working with a coach, playing and studying tactics.  However, one aspect of chess study I want to explore is visualization.

I've looked at articles on the internet and watch YouTube videos, so I am not at a loss for ideas.  However, I'd like to know what exercises other players actively use, especially if you are under 1500.  Let me know.