You can make an appointment to see your doctor online.
http://www.san.gva.es/web/conselleria-sanitat-universal-i-salut-publica/citapreviaYou will need your SIP card number.
From the drop down list of 'Trámites y subvenciones'
Select: Solicitud de Cita Previa
Enter your SIP number and date of birth
Select from which day to look for an appointment and 'from time' and 'to time'
You will be shown a chioce of appointments. Check the box for the required time.
Confirm the appointment.
Occassionally you might get an error message. Just try again and it will disappear.