You just know your pal is making a terrible mistake. But you’re going to need more than your intuition to stop the wedding.

Step 1: Time it

Find a time when you can speak with your friend privately, in a quiet setting. Don’t wait until the last minute (like a week before the wedding)—one to six months before the big day would be ideal.

Step 2: Stay calm

Broach the subject calmly. Your argument is not going to hold much sway if you’re on the verge of hysteria when you deliver it.

Step 3: Be reasonable

Present all the reasons you believe your pal will regret it if he or she walks down that aisle. Deliver them as you would a well-thought-out work presentation.

Step 4: Anticipate objections

Anticipate the betrothed’s objections so you’re prepared to answer protests like, “But my parents will lose ten grand if we cancel the reception hall this late.”

Step 5: Paint a picture

Paint a vivid picture of the grim life you foresee for your friend if he or she goes ahead with the wedding.

Step 6: Offer support

Offer to support the person with the fallout that accompanies canceling a wedding.

Step 7: Offer a compromise

Offer a compromise. Suggest that the person at least postpone the wedding for a while.

Step 8: Accept it

If, despite your best efforts, the person decides to ignore your advice and say “I do,” accept the decision and put on a happy face. Hey, maybe your friend really does know best.