kkkeeek: Use a shorter time setting.
Weekends included, the 14-days per game setting will often come to 20 days per move, which means that your opponent will have 3 weeks to play.
5 days per setting should give you enough time for most of your games, and your opponents will be forced to play faster. Just be carefull about your holidays, if they go over a week, so that you yourself won't timeout.

You can also try Fischer clock settings, where a time is determined for the full game. With the appropriate bonus settings and all, faster players will seldom see any difference, but slower players will soon be forced to play faster.
You can find more about it at the FAQ