When working on detailed images, break the components down into layers.
Example: The Bear. Layer 1: Sky. Layer 2: Background waves. Layer 3: Bears Head, torso & arms. Layer 4: Bears Pants. Layer 5: Boat. Layer 6: Oar. Layer 7: Lifebelt & rope. Layer 8: Bottles of Pop. Layer 9: For-ground waves.
It sound laborious but if you cock-up part of the image, you've only cocked-up that layer as opposed the whole image. So, for every component of the overall image break it down into layers. & will I remember this...
So here is a snippet from the image.
To view the whole image you'll need to sail over here.