Remove each battery cable and clean terminals and cable ends, try starting again.
Other low amp systems can work but starter requires lots of amps, dirty terminals will act that way, if possible check battery voltage as well, should be above 12.3volts.
Starter Relay on the fender near the battery would be the next place to look.
Follow the battery's large Positive(red) cable to the starter relay, when you turn the key to START this relay should "click" closed, this relay passes battery power to starter motor.
The click you hear could be this relay or the EEC relay and Fuel Pump relay, so hearing a "click" doesn't mean starter relay is working.
On the starter relay there will be two Large posts, one hooked to the battery and the other hooked to starter motor.
There will also be a smaller post with an "S" label, when the smaller post gets 12volts the relay closes and starter motor should turn on.
Look at the two larger posts, if connections look dirty, loosen and clean them one at a time, good idea to unhook Negative(black) battery cable at this time, then hook it back up after cleaning.
MAKE SURE transmission is in neutral or PARK, and KEY IS OFF
Use a short wire and hold it on battery + and then touch it to the "S" post on starter relay, relay should click and starter should turn.
If no click replace relay, take pictures to MAKE SURE wires all go back on the same way.
If relay clicks but starter doesn't turn then the starter motor is most likely bad, you should check the cable from starter relay to starter motor, but these usually don't have a problem.
If relay clicks and starter turns then you could have an ignition switch issue, you will need a volt meter to test this.
When the key is turned to START the ignition switch under the steering column slides and sends 12volts to the the Neutral Safety switch(NSS), in a manual trans vehicle this is a Clutch switch, located on the pedal push rod for the master cylinder, when clutch pedal is down all the way the 12volts from ignition switch is passed on to the "S" post on the starter relay, and starter motor turns.
On an automatic trans vehicle the NSS is located on the transmission above the shift linkage, if transmission is in PARK or NEUTRAL the switch passes the 12volts from the ignition switch to the "S" post on the starter relay.
NSS switches can break or get misaligned.