Visualization will help...as will a postitive mental attitude.
Also, try breaking up your study sessions. Four 1/2 hour study periods is better than two 1 hour study periods, which is better than one 2 hour study periods.
If your brain is totally fried. Go out, take a walk, ride your bike, whatever. Get away from it & clear your head. Studying will go better for you afterwards.
And when studying with people...it is good to help others learn. You learn yourself that way too!
Hang in there! You can do it!