How to Collect Extra Stamina

Your Stamina is capped at 120 Stamina points, after which you will not make any more Stamina until you have spent some. Sometimes, it is useful to collect extra stamina over and above the Stamina cap in preparation for a stamina-intensive event. The game allows you to do this at the cost of a March Queue.

What to do
Wait until you are at your Stamina cap (120 Stamina points). Call a rally on a Level 36 Hell Fortress, and dispatch only 1 troop. Ensure the rally is for a full hour. When the hour has elapsed, either dismiss the rally or allow your guy to be defeated. You will now have 132 Stamina points (estimate depending on your "replenish rate").

This is because the game allows points that are "given back" due to failure to exceed the cap.

(Remember that you will not be replenishing Stamina unless you are below the cap.)