Be realistic.
If a role you like becomes available, ask yourself if you could handle the responsibilities and if you have the required skills to carry out the tasks. If you are a bit unsure whether or not you have enough experience, speak to your manager about it and ask him what he thinks. He will probably have a better overview of your capabilities and will be able to offer good advice. Whatever the outcome is, remember that building a successful career takes time and that it is better to progress slowly but surely than quickly and fail.
If you decide to go for it, be prepared.
Most of the time, asking for a promotion is like applying for a job. You will be interviewed to explain why you want the role, what you know about it and why you think you are the right fit for it... Read the job description very carefully and be able to describe each of the tasks you would carry out. You must also think of why you think you can do this role and how your skills and knowledge will enable you to handle it well.
Stay professional and be careful with what you say.
Keep in mind that you are asking for a promotion and not having an interview to work in a new company. Do not denigrate either the firm nor your manager and your colleagues. Stay positive at all times and do not say that you don’t like what you do anymore. Reasons for a promotion can be that you want to have more responsibilities, to be more involved in the company’s expansion or to develop new skills for instance..
Try not to get too excited about it.
You won’t get a promotion just because you asked for one. If the answer is negative, ask for feedback. If it’s because of the interview, you know that you have to prepare it better next time. If it’s because they think that you are not the right person for it, try to know what aspect of your profile wasn’t strong enough (skills, knowledge, years of experience or traits of personality).
Don’t see it as a failure but as the opportunity to improve to get what you want.
Play fair and stay motivated.
Don’t criticize the colleague who got the job or neglect your daily tasks. In this situation, it’s important to put your pride aside and to keep showing your motivation.