What should I check if my truck doesn't do anything when I turn the key?

Are you sure your ignition is good? The part you slide the key into, if it has failed it would do exactly what your describing. Honestly there are a few things it could be on that vehicle I believe the starter solenoid relay would be a good place to start. It is mounted on passenger side fender under the hood and you can test it by putting the key in the on position and using a big flat head screwdriver touch and hold the screwdriver to both terminals on the starter relay the truck will turn over but continue to hold it there until it starts and If it starts then you know it's your starter relay that has failed. It is common old fords. Make sure you test parts instead of just changing them so that you know your correcting the problem with the vehicle

Starter relay as mentioned above. To test it, check for 12.4dc volts on the small terminal of the relay located on firewall while someone starts it. If voltage is present on the small terminal, assuming battery is good and battery cables clean and tight, replace relay. Since you already tested the starter by jumpering it. If no voltage is present on small terminal as you try to start it, trace back to ignition switch or fuse