What to look for in small and desk plants
When a pot is included, half of what you are buying is the pot
On a shelf or a desk the container takes up as much of the view as the plant, and unlike a vase you cannot swap it out later without repotting. Check what it is actually made of — real ceramic and cement have weight and a slightly uneven glaze, while a moulded plastic version photographs almost identically and gives itself away the moment it is picked up.
Look straight down into it
Desk plants are the only thing here seen mostly from above, which is exactly the angle sellers avoid photographing. The centre, where the stems come out of the soil, is where a poor one shows a plastic hub or a disc of bare green foam. Good ones cover it with moss or gravel and set the stems at different heights so there is no single point they all emerge from.
Measure the surface first
These go wrong on scale more often than on quality. A shelf or a windowsill takes something considerably smaller than a side table will, and anything sized for a side table will crowd a desk you actually work at. Measure the space before you look at anything, because a plant that is slightly too big for its spot never stops looking slightly wrong.