Settle on a shape that will work in most rooms. Round tables look good in compact rooms and living areas that have square dining zones. They also offer flexible seating.
As a longtime apartment-dweller, I’ve found that the visual weight of a piece of furniture can really influence how big it feels in a room. It may technically fit, but it’ll seem huge if it’s a dark or bulky piece or if it’s too close to other furniture.
If you want to be more flexible with your guests, pay attention to the leg width and where the legs are placed. In general, a table with thinner legs, or where the legs are at the corners, will make it easier to squeeze an extra chair in.
Trestle tables can give you flexibility along the sides of the table, but can limit space at the ends of it. Look closely at how much space there is between the edge of the table and where the trestle supports are attached to make sure there’s room for your knees.