Teaching posts for September start to appear in The TES round about now.
Many local authorities operate a pool to save students having to complete application forms for each school. Check whether the careers service offers any courses. Some offices may run mock interviews.
Ask your school mentors about their experience of job-hunting and selecting staff. The application you completed for your PGCE is a good starting point. What more can you add? Check spelling, grammar and punctuation, and ask a friend to check it for any errors you might have missed.