Most Helpful Guy
Severe all contact with that person, don't approach them, don't ask them anything even casually, you must convince yourself that the other person doesn't exist. I know it's easier said than done, but that's the best way to ease the pain and get over the other person1
Most Helpful Girl
There is no best way. You just need time.
Go out and meet people. And try to have fun. Do not stay at home. Try to concentrate on sth else.
Find a new hobby.1