How do I make my synclient settings stick?

The default setting for synaptics touchpads includes a paste functionality mapped to the upper right corner of the touchpad. I can disable this behavior by running the command

synclient RTCornerButton=0

But every time I reboot my settings are reverted. How do I prevent this from happening?

You need to put the settings in a xorg.conf file as follows:

sudo gedit /usr/share/X11/xorg.conf.d/60-synaptics-options.conf 

In the new file, type

Section "InputClass"
  Identifier "touchpad catchall"
  Driver "synaptics"
  MatchIsTouchpad "on"
  MatchDevicePath "/dev/input/event*"

  Option "RTCornerButton" "0"

EndSection

Gnome settings daemon may override existing settings (for example ones set in xorg.conf.d) for which, the existing settings in /usr/share/X11/xorg.conf.d/50-synaptics.conf are being ignored. This is how i fixed it.

Run dconf-editor

Edit /org/gnome/settings-daemon/plugins/mouse/ (or /org/cinnamon/settings-daemon/plugins/mouse/ for cinnamon)

Uncheck the active setting

It will now respect your system's existing synaptics configuration.

Then follow monkbroc's solution which will work now.