Answering with a monologue instead of a point
When a question makes you nervous, the instinct is often to keep talking until you land on something good. Interviewers notice the opposite — a long, wandering answer usually reads as unclear thinking, not thorough thinking. Aim to answer the actual question first, in one or two sentences, then add detail only if asked.
Filling silence with filler words
"Um", "like", and "basically" repeated throughout an answer make a candidate sound less confident than they actually are. A short pause to think is far less costly than a sentence full of filler — silence reads as composed; filler reads as unprepared.
Not asking any questions back
When an interview ends with "do you have any questions for us?", saying "no, I think you covered everything" is a missed opportunity. It signals low genuine interest. One or two specific questions about the role or team show you've actually thought about the job, not just about getting it.
Underselling achievements out of politeness
Many candidates downplay their own work — "it wasn't a big deal, I just..." — assuming humility reads well. In an interview, it usually reads as a missed chance to demonstrate impact. State what you did and its result plainly; let the interviewer judge how big a deal it was.