The Patches Of Darkness

This is the toughest jigsaw puzzle I've done so far... Even piecing up the moon itself wasn't easy... The shades were almost the same... The corner pieces surrounding the puzzle were insane! There were few pieces of puzzle that looked exactly the same! This created a 'domino' effect... The minute I joined them together... I realized the other sides don't fit... I had to remove the whole section and redo until it felt right to me... With countless trial-and-errors done, I FINALLY completed the border... And now? Patches of darkness... So please advice me where do I start??? Time is running out... Arghhh...