From what I've seen is that the subject matter at night will need some light on it for the focus to take hold.
With the fixed f2.2 at 28mm the camera has a wide view so if the target isn't lit well it may work best to get close for handheld shots.
I find things like park benches, walls with a straight edge, the "Y" of a tree or any stable surface works to help steady the camera in low light.
Also play with the exposure value slider in Lumia camera this can overexpose for a desired effect.
Things like city skylines over water always look striking at night because of the amount of light.
If you look at most night shots that are handheld the best ones are sufficiently lit.
A pocket tripod is still most handy for the artful photog using a phone camera in my opinion...
Good luck there!