Survival strategies in solitary confinement can be summarized as follows:
Visualization
Imagination
Memorization
Reconsideration
Determination
Visualization: Visualize imaginary scenes and conversations including outright talking out-loud
Imagination: Make your imaginary world visually vivid.
Memorization: Memorize i.e. review mental knowledge; mental math, mental vocabulary etc.
Reconsideration: Look back at past events especially the bad ones to determine what went wrong, why, and what you would do differently; this too is a visualization and scripting exercise.
Determination: Set difficult long term goals and never ever give up on them.
http://nautil.us/issue/32/space/how-to-survive-solitary-confinement
How to Survive Solitary Confinement