1. Being unprepared
Do your due diligence in preparing for the visa process. Data on the visa process and interview are widely available on the internet. Government sites are also reliable resources that contain information to assist you every step of the way.
2. Applying for the wrong visa
Depending on what type of visa you are applying for, the eligibility and requirements may differ. Double-check that you are indeed applying for the proper visa. Make certain that you can fulfill the requirements and meet the conditions for that particular visa. Don't make pre-assumptions on your eligibility for a certain visa just because you fit the criteria for another visa. The standards may differ with each visa.
3. Providing incorrect or insufficient information
Completing all forms accurately and being fully prepared with all requirements, documentation, and forms of verification can help expedite the process. Having unverifiable or inaccurate information can lead to visa denials or prolonged and redundant processing. Don't let a small oversight lead to delays in obtaining your visa.
4. Being overly confident during the interview
Being too assertive on all aspects of the visa process or expressing extreme confidence of a visa approval during the interview can make you come off as presumptuous and arrogant. Try not to present yourself as a 'know-it-all' or 'wise guy.'
5. Giving too much information
As you can expect, you will be asked an array of questions. Your responses should be well-thought-out, but keep them concise and simple. You don't need to divulge irrelevant details that don't pertain directly to the inquiry, nor should you voluntarily give up information that isn't requested. This can actually lead to more questions or raise red flags and suspicions that would have otherwise not arisen.
6. Being disrespectful to the interviewer
Start with an attitude of respect, even if the interview may seem tedious or tiresome. You can do this by expressing humbleness and courtesy toward the interviewer and submitting to the authority they represent. Also, having a messy appearance may appear to show a lack of seriousness in the process.
7. Ineffective communication
Sometimes the language barrier, various accents and dialects, or unfamiliar lingo may leave you confused. Don't hesitate to ask the interviewer for an interpreter or to repeat, explain, or slow down. Effective communication can help avoid potentially significant misunderstandings and misinterpretations.