Pay most attention to the fit and length of your jacket. It should end at half an inch above the shirt’s sleeve. A piece with sleeves too long or short could single handedly degrade your look, despite perfect fabric, buttons, vents and lapel.
Grey and navy blue colours are appropriate for everyday work wear; black is mostly a colour of choice for formal occasions.
When pairing the suit jacket with a pair of jeans, avoid unnecessary cuts and patterns. Hem the ankle portion of the jeans if needed. If not, opt for chinos as an alternative, younger option.
Even though the suit jacket is a versatile piece of clothing, it’s often worn more with trousers.