We've designed dozens of tablescapes here at the Cottage, but when the cameras are put away, I've found that the most tried-and-true small space-friendly tabletop items are almost always a combination or selection of the following:
Rectangular: It's much easier to fit everything on your tiny tabletop (whether you're setting up a dining space for 2 or 6) if you use rectangular plates. Instead of adding napkins and silverware on either side, try dressing them ON TOP of the dishes.
Stackable: Sets of mugs, cups, and plates that sit safely on top of one another (on the table and/or within your cabinets) are great for keeping your kitchenwares compact and organized.
Custom-sized: Regular placemats and tablecloths are usually comically oversized for little tables. Try using a 2-person placemat-- or simply cut a runner down to size. Drape it over the table for face-to-face dining, or simply use it as a narrow tablecloth for side-by-side counter dining.
Caddies: Keeping your silverware at the ready via caddies is an effortless way to save tabletop and drawer space.
Vertical: Select vases, candles, and pitchers that have a small footprint, and extend upward (rather than horizontally) to liven up your table without cramping your experience.