Candle_IKEA.blend (931 KB)So i tried to make a realistic looking candle, this isnt serious work. I am new to blender so it would help with some tips 
A lot of the problems you’re having come from having a low poly model.
for example, here is you project as provided.
If you improved the “resolution” of the model a bit you might have better results. in the following image, I added a subdivision surface modifier.
this lets the light paths be simulated more realistically. I also replaced the “toon” shader on the wick with a “defuse” shader, As it looked a little odd when it was pure black right next to the flame.Candle_IKEA.2.blend (962 KB) hope this helps
I love your wax texture btw :yes: