Areas, tasks, materials, owner labor, employee labor, buffer, margin. Guessing is not a step.
Step 1: Define areas. Step 2: List tasks per area. Step 3: Price materials per task. Step 4: Calculate owner labor at floor rate. Step 5: Calculate employee labor at loaded cost. Step 6: Add 10% buffer. Step 7: Apply gross margin to produce the selling price.
The client sees the selling price only — never cost, margin, burden, or buffer. Each step builds on the one before. Skip any step and the estimate is structurally flawed.