After repeated stops my 1997 subaru outback will not start

Rule of thumb is Compression , Fuel, Ignition.
Check compression with a compression tester in the spark plug holes.
Make sure fuel is getting in to your motor ( when you remove the plugs check to see if they are wet , too much fuel , or burnt, not enough fuel )
Ignition: With the plugs out, connect a sparkplug to the plug lead earthing the base of the plug, wind the motor over. You should see a spark jump across the gap at the base of the sparkplug.
Once you find which bit isn't working, find out why.
Happy hunting