6 ways to show Depth

Linear perspective: 

1. Supermarket aisle
2. shelf 
3. Cart
4. Tire marks

Overlap:

1. Fatcake
2. Characters, in the cart
3. Supermarket cart 
4. Carts Smoke

High/low Placement:

1. man chasing cart
2. Fatcake
3. boxes at top shelf 

Size changes:

1. Shelf
2. Boxes
3. Cart

Loss of detail:

1. shelf
2. products/boxes

Colour:

1. Colour of boxes