People

To draw people, find images of people in the poses you want.

Take notice of the angle they are being viewed from, and that it is suitable for your drawing.

Cars

Take the same approach with cars. Locate images with the point of view in mind. Trace them, then scan. These can be scanned separately and added to your Photoshop file as a new layer.

Use ellipse guides for the wheels, if they are large in size.

Textures

Brick

Brick needs to be in perspective. Follow horizontal lines to vanishing points. Apply vertical lines alternating as brick tends to do. Observe the source drawing. Do not be literal and draw every brick; fade the level of detail as the wall recedes.

Cement

Make small pits here and there. Show seams.

Grass

Draw light lines following the contour of a hill, etc. Make very short vertical strokes indicated grass. As the scene recedes into the distance, eliminate the lines and let the color take over.

Reflections in windows

Acquire an image to go into the reflection. Paste it into the window selections. Distort if needed. Fade back opacity. Duplicate the layer, changing the blend to multiply; this should also have transparency.

The window reflection on the right is added:

Reflection of a building in still water below

Duplicate the building and flip both horizontal and vertical.

Apply render/glass or render/ocean ripple.

Make a textured ground plane that recedes

Apply noise to a flat color

Scale up the “near” edge ... see the edges zoom out ...

Duplicate the layer and gradient-mask out the bottom ...

Blur this new layer

Here it is: