What test design techniques do you follow when writing automated tests?

When writing automated tests, I use the following test design techniques:

• Equivalence partitioning — dividing input data into equivalence classes to cover different scenarios without redundancy.
• Boundary value analysis — testing behavior at the edges of permissible values.
• Tabular testing — convenient for checking parameter combinations.
• State testing — for systems with different object states.
• Positive and negative testing — verifying both correct and incorrect scenarios.

These techniques help create effective, understandable, and maintainable automated tests.