When shopping around for the perfect bedside table lamp, you need to think about getting the height right so it doesn't swamp the area and overwhelm the space. You need to consider the height of your bedside table, if it is the same height as the top of your mattress, the maximum height you can go is the same height again. If your bedside table is lower down, you can go for a taller lamp.
Use your headboard as a guide to help you make a decision on height. Anything taller than half the headboard should be ditched in favor of something smaller. If you are looking at floor lamps, any height that is taller than the headboard could work if it's in the corner of the room.
I also like the mini table lamp trend which works for small bedrooms and if you have a mini bedside table. They are super cute, add a touch of decor without taking up too much space, and are often cheaper than the full-size designs.