Sean, first, check fuse #19 (25 amp) in the front fuse box. This feeds power to the starter to engage the arm and allow the starter to get power. Next, if you look on the top of this fuse, you will see 2 metal tabs stick out of the top of the fuse. Pick either post and connect the red lead to the post and the black lead to chassis ground. When you are attempting to start the car, do you get 12 VDC (more than 11.0 VDC) at this point? If you are getting 12VDC, then you have either a bad starter or a bad power wire (either between the relay and the starter or between the starter and battery). If you are getting something in the in between (less than 11.0 VDC, but not 0), then you most likely have a bad relay. If you are getting 0 VDC, then you will need to remove relay #10 (starter relay) and first connect the red lead to pin #1 of the open relay spot and chassis ground to see if you are getting 12 VDC when attempting to start the car. If no, then you have a bad ignition switch or bad wire between the ignition switch and the front fuse box. If yes, move the red lead over to pin #2, place the multimeter on the resistance setting and when you attempt to start the car, verify that it falls to something less than 50 ohms. If no, then you have either a bad engine control module (ECM), a bad wire between the relay and the ECM, or the coding for your key has been lost. If yes, then most likely you have a bad starter relay. Replace the relay. Before replacing the relay, verify that you are getting 12 VDC on pin #3 when attempting to start the car. If you are not getting 12 VDC, then you have a wiring problem between the ignition switch and the relay.

Hope this helps.