Be Clear and Specific

Vague in, vague out

"Make this better" or "write about dogs" leaves the model to guess your goal, length, tone and audience. Replace vague words with specifics you could check: "Rewrite this email for a customer who is angry about a late delivery; keep it under 120 words; apologise once; offer a refund or reshipment; plain, warm tone." State the goal (why), the audience (who), the constraints (how long, what style, what to avoid), and what done looks like. Positive instructions ("use short sentences") usually work better than only negative ones ("do not be wordy"), though both help.

Be specific, show examples, set boundaries

Clarity, examples and constraints solve most prompt problems.

Vague versus specific

The same request written two ways.

VAGUE
  Summarise this report.

SPECIFIC
  Summarise the report below for the CFO in 5 bullet points.
  Focus on revenue, costs and risks. Each bullet under 20 words.
  Quote any figure exactly as written. If a figure is missing, write "not stated".

Say what "good" looks like

Add a checkable success criterion, such as "each bullet under 20 words", so you can test the output automatically.

Quick check: Which prompt is better?

• "Summarise this"
• "Summarise for the CFO in 5 bullets, under 20 words each"
• "Do something useful"
• "Be smart"