Know what you want – first of all, decide whether you really want the job advertised. It’s all too easy to be tempted by a vacancy in your workplace, especially if the job pays better than yours. Make sure this isn’t your only motivation. It has to be a logical role for you to take. There’s no point stepping sideways into a different department, for example, just because you’ll get more money. But if the job is a great opportunity to advance your career then you have nothing to lose.
Don’t be presumptuous – don’t assume that just because you already work for the company that you’ll get the job. If anything you will have to work even harder in your interview as people you work with will already have their own opinions of you and how you fulfil your current role. Remember companies often like to employ new talent, so you have to convince them that you’re the best person for the job.
Keep quiet – even if you get on really well with your colleagues, that doesn’t mean you have to tell them that you are applying for the role. It could be potentially embarrassing if you aren’t successful. The other danger is that on hearing you are going for the job, others might follow suit when they hadn’t previously considered it. Workplaces are generally rife with competitive people, and the fewer employees that apply for the job the better it is for you. You should also be able to rely on your HR department not to say anything – job applications should be considered confidential.
Use your judgement – as you will probably know the person interviewing you, the situation may not be as formal as it otherwise would be. But be careful not to appear casual. Remember it is still a job interview and you should behave appropriately. Make sure you are smartly dressed, even if you are smarter than you would be on a normal working day – it shows you are serious about the application and that you are making an effort. Another benefit of this is that your interviewer will see you aren’t assuming that you’ll get an easy ride and that the job is in your pocket already.