You can try to disable or kill some cpu/internet hungry background services or processes in windows
The old Gamebooster 3.5 beta from iobit (before razer took over) is a nice and easy software to do this (win 7/Xp) If you dont know to make a batchfile yourself
If you have old harddrive try to defrag it
Disable other users sharing same internet connection
If wireless, put antenna in a better place ex. outdoor on top of building in proper direction