The moment I notice a coffee table set is working is when someone sets a mug down, then a plate, then a phone, then a remote, and nothing is balanced on the arm of the couch or the floor. That is the whole job. One good table and one or two smaller ones that can split off and do their own thing when you need extra surface for game night or a kid's puzzle.
If you have nothing right now, start with the basic pairing, one coffee table and a set of nesting tables, rather than a coffee table plus two matching end tables. The nesting set gives you more flexibility per dollar, and you can tuck them away when they are not needed instead of having end tables stranded with nothing on them. For sizing, measure your seating first, not the table. You want about 14 to 18 inches between the table edge and the front of the sofa, enough room to walk through without clipping your shin, and the table top should sit roughly level with or a little below the seat cushions. The mistake almost everyone makes, myself included in our first apartment, is buying the table that looks right in the showroom and then discovering it eats the whole path to the kitchen. Measure the actual floor space with tape before you order anything.
These sets work best in the rooms where people actually linger, a living room obviously, but also a finished basement, a sunroom, or a small den that doubles as a guest space. In a tiny apartment living room, the nesting version earns its keep because you can pull a second table over for a laptop or a dinner plate and push it right back when you need legroom. In a bigger family room, a coffee table with a shelf underneath plus a couple of side tables gives you storage for the stuff that otherwise lives on the floor, remotes, coasters, the dog's chew toy that always ends up under the couch.
On finish, I would steer toward a warm wood tone or a simple matte black over anything glossy or glass. Glass looks sharp for about three weeks until it is covered in fingerprints and water rings, and then you are wiping it down before every single person comes over, which gets old fast. A medium wood tone forgives scuffs and matches almost anything you add later, whether your sofa is gray, navy, or that beige everyone seems to end up with eventually. Living room budget was $350 for the table set. Spent $295, and the leftover went to a lamp, not the takeout Mike was lobbying for.