Ping is the time taken, in milliseconds, for a packet of data to make the round trip from your computer to the server and back.
Your speed doesn't directly affect your ping.
Instead, look at your connection - if it's wireless, go wired. If it's wired, try to use a shorter cable, possibly a better quality one.
On the ISP side there's nothing you can do really, at peak times you'll get high ping because more people are on.
Servers with less people, and those that are closer to you, will generally have a lower ping too.