You might want to light candles and incense as reminders of impermanence, but you can also have a plain wall in front of you.
If you like, you can make a small altar of some kind and decorate it with pictures or photos and sacred objects from your own tradition. You might want to light candles and incense as reminders of impermanence, but you can also have a plain wall in front of you. As long as you are not sitting in front of something distracting, like the TV or the desk where your computer lives, it doesn't matter too much what is in front of you.