Step 1. Guidelines

When drawing the face from the side, start by drawing a circle for the dome of the head, a triangle towards the front side of the face for the jaw, a triangle in the front middle of the face for the nose and a rectangle for the neck. Make sure to draw these lines in lightly because we will erase away these lines when we add in the features.

Step 2. Facial Features

The Eyes

When drawing the eyes from the side they will have a triangular appearance and be much shorter than usual because we will only see about half of its full size.

The Nose

Once we have the triangular guideline of the nose from the pervious step, we just need to add the underside and the nostril. I have a line by line tutorial on drawing the nose that you can check out here

The Ear

For the ear you start by drawing the outer shape and then add the inner details. Drawing the ear is slightly easier from the side view because we dont have to draw as much perspective, I have a line by line tutorial for the ear here that you can use. 

The Lips

To draw the lips start by drawing two lines that meet at a point in the middle, these two lines should be angled slightly towards each other. Lines that connect to the three points of the previous lines and extend them horizontally, the center one being flat while the top and bottom lines converge towards the middle. You can connect these lines at a point if you like but you can also leave them open like I have in the example for a more minimal look.

Step 3. Hair

Block-in

If possible, draw in a large shape that has the general shape of the hairstyle you are drawing. This will make it much easier to draw in the detailed lines of the hair without losing the overall shape. For flowing hairstyles, this will not be a useful step. 

Details

Draw in the detailed lines of the hair and add rendering. I have hair drawing tutorials here that you can check out and also a hair drawing workbook below that you can use to learn the basics of drawing hair.

I have created a workbook to help you with these steps that you can grab below if you are interested! I hope this was useful to you and also check out more tutorials on the site~