how to impress:
show up at least 15 minutes early.
wear a necktie (clip on is actually better in case it gets caught in something)
be clean, shaven, taken a shower ...NO cologne or aftershave lotion.
ASSUME you will be given an engine failure scenario on the first takeoff.
have current charts. make xerox copies of all of your licenses/medicals etc. offer the copies to the interviewer (have your orginals with you for examination).
have a weather briefing for local flying work prior to showing up .
be upbeat, use "SIR" or other respectful forms of address, not YOU GUYS or whatever Belgium slang there is.
WATCH OUT FOR LITTLE things like doors not shut properly , seat belts, etc.