What is important in a technical interview?

Technical Questions:

"The way the interviewer approach the problem is more important than the skills and experiences"

1: Process
Took the problem.
Understand the problem.
Design basic test-cases.
Conceptual Idea.
Mathematically check the correctness. 
Design the Data Structure and Algorithm.
Code Reviewer.
Testing the solution. (Functional -> Boundary -> Wrong Inputs)

2:
Communicate with the interviewer.
Do you have suggestions?
How do you think?

3: Skillset
1) Writing good code (production code)
2) Algorithms and Data Structure (big O notation)
3) Analytical skills (questioning the problem and think through the solution step by step and mathematically check the solution is correct)
4) Sound Design (Testing)

4. Tips
1) Do not optimize before correctness.
2) Time/Space trade-offs
3) Assumptions
4) Ask if cannot remember APIs
5) Must Test (boundary conditions, etc)