How do I troubleshoot a Ford Focus engine that won't start?

My friend's Ford Focus engine won't start and they're trying to figure out what could be causing the issue. Can anyone provide some insight on how to troubleshoot this problem?

First, check the battery and make sure it has enough charge. If it does, then the issue could be with the starter motor or the ignition system. I would recommend bringing it to a mechanic for a proper diagnosis.

I had a similar problem with my Ford Focus and it turned out to be a faulty fuel pump. Have the fuel system checked to see if that could be the issue.

Another common issue with Ford Focus engines not starting is a faulty crankshaft position sensor. If this is the case, it will need to be replaced.