Well, there are many different ways to decrease ping.
1st. Buy a better internet connection or call them and tell them to make it GAMING internet connection (on my internet company, they call it "Fast Path", as we did.. from 102 ping went to 42-51 ping on EUROPE, on NA from 95 to 36-48).
2nd. Try by downloading CCleaner, will clean every sht you got like everyone else, go windows start, type CMD and press Enter, type on CMD "ipconfig /flushdns".
3rd. Try GameBooster.
That's all I know to reduce ingame pings.. 2nd way works on me.. I got low ping and reduces 5-10.. when I had BIG ONE.. reduces 10-20... not kidding!
COPY PASTE BETTER : ipconfig /flushdns (with a space beside of ipconfig and "/")