When you emerge from a job interview your head is often a whirlwind of energy as you question whether you said the right thing, did the interviewer like you, do you think you got the job? It is only natural that following this kind of experience you want to follow up and find out your situation as quickly as possible. However, it's important to make sure you achieve a balance between inquisitive and annoying...
What to do:
A positive step you can initially take is merely to email a thank you message to the relevant department, in such a way that will probably bolster their impression of you and will hopefully remind them to get back to you as soon as they can.
When you finish your interview, you should always make sure to confirm with the interviewee when to expect to hear back from them. If it goes beyond the established date and you are beginning to get antsy, it is perfectly legitimate to make contact with them. While you may be tempted to phone them there is a risk of coming across a tad pushy. A well phrased email means you won't be putting anyone on the spot. You should make sure to include a reiteration of you thanks as well as inquiring if they need any additional information. At this point all you can do is sit back and wait and your respective interviewer ought to get back to you as soon as possible and will hopefully respect your inquisitive attitude.
What not to do:
Don't go overboard with your attempts at contact - if you try and meet them in person or direct at them a barrage of emails and phone calls you are more than likely to frustrate your potential employees and ruin your chance!
Don't be overly informal with your thank you message - there's never any need to include any kind of emoticon :( and if you are too gushing with your grateful language, potential employers are likely to be able to pick up the annoying whiff of sycophancy - keep it professional and you could bag yourself a profession
Don't play hard to get - in your email correspondence never develop a pushy tone along the lines of 'I have a few offers to consider at the moment so could you please get back to me as soon as possible.' No one appreciates arrogance and you should always strive to make it seem that the job you are discussing at hand is your number one priority.
Overall, the key to following up effectively is to achieve a careful balance between inquisitive and imposing. With the right kind of tone and content you can go a long way to enhancing your job prospects or at least finding out your current situation sooner rather than later.