Most candidates prepare for interviews by solving problems alone on LeetCode. Then they enter the actual interview, the camera turns on, the interviewer is watching, the clock is ticking — and suddenly they can't think. Their hands shake. They forget how to write basic code.
The problem isn't knowledge. It's that they never practised under conditions that resemble an actual interview. Mock interviews fix this. Here are the 10 most effective techniques.
Start Speaking Before You Start Coding
The single biggest mistake candidates make is going silent and thinking internally. Interviewers at FAANG companies are trained to evaluate your problem-solving process, not just your solution. If they cannot see how you think, they cannot give you credit for thinking well.
From the moment you read the problem: narrate your observations. "This looks like it could be solved with a sliding window since we're looking at contiguous subarrays..." Even wrong initial observations are fine — they show you're engaged and iterating.
Treat Mock Interviews as Real Ones — No Notes
Most people do "mock" interviews with their notes open, a LeetCode solution nearby, and their phone in hand. This trains the wrong habits. In a real interview you have none of these. Your mock environment should mirror reality: blank editor, no browser, camera on, timer running.
Ask Clarifying Questions Before You Write Any Code
Spend the first 2–3 minutes asking questions. Confirm input range, edge cases, whether the input is sorted, whether you can modify the input, what to return on empty input. This does two things: it prevents you solving the wrong problem, and it signals maturity to the interviewer.
Verbalise Your Brute Force Before Optimising
Always describe the naive O(n²) or O(n³) solution first, even if you know a better one. Say: "The brute force would be nested loops giving O(n²) time. Can we do better?" This communicates that you understand the problem space, and gives you a base to optimise from. Jumping straight to an optimal solution without explaining your reasoning is a red flag.
Record Yourself and Watch It Back
This is uncomfortable. Do it anyway. Record one of your mock sessions and watch it back within 24 hours. You will immediately see: long silences you didn't notice, filler words ("um", "like"), nervous laughs at the wrong moments, and — most importantly — whether your explanation was actually coherent. Self-review is faster feedback than waiting for an interviewer.
Create a Feedback Journal — and Actually Use It
After every mock interview, write down: (1) what pattern the problem tested, (2) what you got wrong, (3) what you would do differently. Most people review their answers once and move on. The ones who get offers review their patterns weekly and track which weaknesses recur. A single notebook or Notion doc is enough — the habit matters, not the tool.
Practise With a Real Human — Not Just Yourself
Solving problems alone builds knowledge. Solving them in front of another person builds the interview skill. Find a peer, use platforms like Pramp or interviewing.io, or book a session with a coach. The discomfort of being watched is exactly the muscle you need to train. Without it, you are preparing for a different test than the one you'll sit.
Always Dry-Run Your Code With an Example
Before saying "I'm done", trace through your code manually with the example input. Better yet, choose a small custom test case. This catches off-by-one errors, null pointer issues, and wrong base cases that would cost you the offer. Interviewers watch this step closely — it separates careful engineers from careless ones.
Prepare 5 Behavioural Stories Using STAR Format
Every FAANG behavioural round asks variations of the same 5–7 questions: a time you disagreed with a colleague, a time you failed, a time you had to influence without authority, a time you had to make a decision with incomplete data. Prepare structured stories in advance using Situation → Task → Action → Result. Improvising in the moment leads to rambling answers that forget to mention results.
Schedule Your Mock Interviews at Your Real Interview Time
If your FAANG interview is at 10am, do your mocks at 10am. Not 9pm when you're in the zone. Cognitive performance follows the body clock, and the same problem that felt easy at night might feel hard in the morning if you are not accustomed to that time. Small edge but worth 5 minutes of calendar scheduling.