Hey! I’ll show you have to make pet faces.
I will be using Photoshop. I’m also sure you can do this on different programs, and there are a lot of other tutorials on other sources! Let’s begin.
First, make a new layer.
Select the Ellipse tool. (Shortcut - U)
Make a circle. (Preferably white, but it’s up to you!) NOTE: I made the background a dark color so I can see what I’m making. (Hold shift while dragging the tool to make a perfect circle.)
Make another circle, and you may make the color black. I placed it at the top right corner of the cornea, but you can place it anywhere you like!
Make an oval, and place it at any end of the eye. (To make an oval, just make a circle and form it into an oval. Drag the top down, but not too low. It should make an oval.) This should create a shiny effect to the eye.
Make an oval vertically, and make it any color you want. I made mine gradient.
Make yet another vertical oval, and make the color a bit darker than your first pupil. Add a drop shadow if you want. I added a drop shadow, but it’s all up to you!!
Now, you can add any detail you want to add to the eye! I made a rounded X shape.
STEP 2
Let’s move on to making the eyebrows! Select the pen tool.
Make your fill color black, and no stroke.
You can make your eyebrows sharp cornered, or round cornered. I’ll be doing round cornered eyebrows.
To make round eyebrows, go to your stroke options.
NOTE! Make sure you select a preset. If you don’t your changed settings for your eyebrows won’t apply!!
Once you have selected a preset, these are the ones that you’re going to modify: Align, Caps, Corners
Select everything in the middle. I couldn’t take a screenshot, because none of the methods work. The settings disappear once I take a shot, so I’m sorry.
Make a line, and in any direction! I’ll make a diagonal line.
Once you’re finished, copy your finished eye and align it with the first eye. Make sure to select the copy first, right click and click Flip Horizontal. Move it away from the first eye, but make sure it’s aligned with it.
Now, do the same to the eyebrow.
If it doesn’t look aligned, you can always move them. There are automatic positioning guides in Photoshop. 
Moving on to the mouth, it can also be round edged or sharp edged! Any shape you want will do, and of course you may add any details you want to your face. 
Thank you to anyone who views this tutorial, I appreciate it! If you have any questions about this tutorial, you may leave it in the replies. I’ll try getting back to you asap!