Question every requirement, regardless of who gave it to you. Every requirement must be tied to a specific person rather than a vague department.

Subtraction is key. If you aren't forced to add back at least 10% of what you delete, you aren't deleting enough.

Only after questioning requirements and deleting unnecessary parts should you begin to simplify or optimize what remains.

Once the design is lean and necessary, focus on increasing speed.

This is the final step. A major mistake is attempting to automate processes that should have been simplified or deleted first.