Research before interviewing:
Engineering blog: Most companies publish technical posts. Learn their stack and challenges.
Conference talks: Engineers present at QCon, Strange Loop, company-specific conferences. Watch recent talks.
Job description: Hints about the team's focus. Mentions of specific technologies.
Glassdoor/Blind: Interview experiences from others. Take with grain of salt but useful for format.
Product usage: Use their product. Notice UX decisions. Think about backend implications.
News: Recent outages, launches, or pivots. Shows you follow the company.
Goal: Speak their language. Reference their challenges. Show genuine interest.