A blazer already has its own architecture: shoulder line, lapels, closure, pockets and sleeve buttons. Accessories should reinforce one of these elements, not compete with all of them. Try the blazer both open and fastened before deciding what to add.
Give the lapels space
A necklace should sit clearly inside or outside the lapel line rather than disappear beneath it. A brooch works best when the fabric can support its weight without sagging or leaving damage. Strong earrings are often the cleanest option when the lapels and shirt collar already create enough detail at the chest.
Connect hardware carefully
Buttons, belt buckles, jewellery and bag fittings do not need to match exactly, but they should belong to the same visual conversation. Repeat one finish and allow the others to remain quiet. Avoid a shoulder strap that crushes padding or creates shine on delicate wool.
Test the working version
Put items in the pockets only if they can hold them without distorting the front. Sit, type and raise your arms with the bag and outer coat. The blazer should still close, the sleeves should not catch on bracelets and the accessory should remain useful beyond the first photograph.
