When wearing a three button jacket, you can sometimes do the first and second button done up. This rule only applies with a three button jacket. If it's a four button jacket, it may be an abomination threatening to ruin your sense of style so reconsider its place in your wardrobe.
When standing or presenting to a group of people, always have your top button done up. When you sit down, undo the jacket and leave it open. This will stop your jacket from bunching when you sit and when you stand and do it up, you'll look put together but not like you're trying too hard.
Do up the bottom button. You'll risk looking too congested and it's likely to pull across your chest and backside making for unflattering angles.
Images via: Pinterest and GQ.
Alarna Hope is a personal stylist and blogger based in Sydney, Australia. She loves makeover movies like Crazy, Stupid, Love and Devil Wears Prada and she's very good at talking about herself in the third person. You can find her on instagram @alarnahope or searching through clothing racks in Sydney City's shopping precinct.