Start with the piece causing the most trouble
Before you buy anything, look at the room and ask one deeply unglamorous question:
What is annoying me most?
Is the dining table too big?
Is the sofa blocking the room?
Is the coffee table constantly attacking your shins?
Is there nowhere to put books, keys, remotes, chargers, candles, school forms, sunglasses, receipts, and the one Allen key nobody is brave enough to throw away?
Small spaces need problem-solvers, not fillers.
A good piece of furniture should earn its spot. If it cannot store, seat, hold, hide, extend, tuck away or make the room noticeably better, it may simply be standing there looking expensive.