When the interview is over you can still benefit from the experience and prepare for the next stage.
Notes are useful if you are invited back for a further selection stage; a second interviewer may probe further on particular issues and your notes will help you prepare for these questions. After the interview try and note:
The interviewer will normally have explained what happens next and when you are likely to hear about a decision. If you have not heard from them by the time they said they would contact, then it is OK to send an email enquiring when they hope to let you know. Don't pester them, however, as they may just be a bit delayed.
If you are unsuccessful it is OK to request feedback (by email is probably best) to help you for future interviews. Whether you will get this depends on the employer’s policy, so if they cannot give feedback don’t question this.
In the unfortunate event that you consider there has been discrimination in the recruitment process, for further advice and information see www.prospects.ac.uk.