Excuse my English grammar. For composition, my advice is to check your perspective precisely. The camera angle is lower than the candles; why the upper surfaces of the candleholders are still visible? Also, you don't always want to wrap every object with monotonous lines, even with hairs. Your lines are not very defined and lack variety(thick and thin). Try to draw with your shoulders more to have clean and straight lines. For the brightness of the color, try to switch the whole thing to grayscale (if your painting digitally) and darken it, then subtly highlight it up. If the construction of the painting is not strong, your painting will most likely look distorted and unattractive, even with fine coloring skills. It's best for beginners to start with easy paintings and copy other's works instead of guessing as you draw. I hope this helps.