No easy way but try to keep busy doing things .. try doing things you haven't done before, maybe nightschool, charity work etc. Getting out there and meeting people is far better than sitting at home on your own.
throw all things that remind you of him/her away. Don't keep anything!!! Write a letter and burn it. After that watch
listen to a love song, cry and then watch a horror movie. You will soon not remember him /her anymore.
I agree with Tartanwizard that getting out with your friends is good. WendyW is right about doing stuff - evening classes etc. It helps not to idolise you ex-partner and not to remember just the good times. Unless he/she was a God(dess), there must have been some annoying habits/ arguments etc to focus on!
And better luck next time.
be kind to yourself. be inspired in your use of time. ENJOY
the luxury of being single. don't romanticise the past or despair of the future. learn from it and move on.
The quickest way might not be the best for you in the long term, grief takes it's on time, you can't hurry it, but it doesn't help to dwell unduely on it either. Get out and get your life back, don't mope, your emotions will take care of themselves.