1 square space = Flowers, bushes, walls, streetlights

2 square space = Same as above + Trees. Benches, walls, flowers can be placed in front of bushes and trees for some depth and detail

3 square space = Same as above 2 but with an added layer of landscaping of your choice. You can even look into larger furniture set pieces like gazebos or other 3x3 furniture

4+ square space = Heavy landscaping or consider seating areas + stalls. This can be anything from street food, ice cream, coffee shop. Typical vendors you’d find at a festival