It is very difficult to find the concentration in a stressed or tired brain , because the solution that obvious , relaxation is the main thing to focus on, there are several methods like hypnosis , or simply listen to soothing music, or something that relaxes you , I recommend hypnosis , you can find some online video , you can move from one state to a fully awake tired with your senses to one hundred
Excuse my translation , I do not understand the English