Make sure you have got a good ISP which offers fast connections. For the full lowdown on optimizing your modem and system settings check out Tweak3D's Modem Tweak guide . Also, games have their own changeable settings which can improve your ping for that particular game. Quake 2, Half-Life and Sin all use practically the same game engine and this can be configured and optimized the same ways through placing settings in a file known as the autoexec.cfg found in the game folder. For a easy autoexec.cfg creator use Tweak3D's Autoexec creator which will create you own customized autoexec file for Quake 2, Half-Life or Sin.
Every setting is explained and can be changed with the click of a mouse.
It is amazingly easy and believe me it helps lower ping. Winmodem, NO V.90. No modem or system optimizations made. Winmodem with V.90 support. Half-Lfie autoexec.cfg unchanged.