STEPS

Start with drawing a horizon line and placing 2 vanishing points. You are going to start with the base first. What is the closest part of the base? - the front edge!

Draw a vertical 1" line for the base front corner.

Draw receding lines to both vanishing points:

Use the "grid" technique to create a checkerboard base form.

Draw a horizontal line through the corner.

Divide it into equal segments based on the number of squares.

Sometimes you might want to expand that line past the borders of your drawing.

Draw a grid. There is no need to draw the receding lines all the way to the vanishing points - you can stop at the bottom of the base form.

Define the squares on the sides of the base with vertical lines.

Define the top side by drawing two receding lines from the back corners.

Connect the grid marks of the top side with the two vanishing points.

Erase all unused receding lines. Your base is done.

Now it's time to place the box on top of base:

Mark the perimeter of the box on the base's grid:

Once you define the area for the box - draw the closest element of the box - the front edge.

Divide it into equal parts, based on the number of squares you want to have on the box sides.

Connect the marks to both vanishing points.

Draw the other two corners with two vertical lines.

Each side of the box can be viewed as a grid in 1 point perspective.

Draw a diagonal line on each side.

Draw vertical lines through receding and diagonal lines crossings.

Add the top side.

Complete the grid on the top side.

Erase all receding lines that are not in use.

It's done!!!

Shade the grids: