First of all I hope your exams went smoothly.
i dont know what the effect you were going here was my friend, but trust me when i say you need to move around. missing a shot because you stayed in the same spot for too many frames
In essence, what was explained to you was about the lack of variation in viewpoints that you took of this Christmas tree. They're pretty much all from the same angle, and that is a problem. You need to consider your composition.
The lack of contrast and the brightness to the right of the frame is down to severe flaring caused by a bright light source that was shining into the lens. If you had varied your position so that this light source did not shine into your lens, then you wouldn't be having the flare and contrast issues. Beyond that, there's also a need to think about composition, exposure, and adequate support for your camera in low light. MBrutus2009
has given some simple pointers regarding settings. There essentially are no rule of thumbs in low light photography other than being able to have a means of getting your camera steady. Once it's steady then you can lower the ISO, close down the aperture iris and use longer exposure times.
Essentially this all encompasses the problems seen in your images, and despite what you've said, I'll still be sympathetic.
Thanks for sharing.
, EXIF is ISO1600, f/3.2, 1/13, 100mm equiv. for the 1st image. The other images display similar technical discrepancies.