Example (click to enlarge):
In the above profile view you can see some of the minor differences in the lines of the stitching on the side. Also note the difference in shape as it wraps around the back. You can see the difference in the toe of the sole too.
Example (click to enlarge):
The rubber toe cap of the fake has a flatter edge, whereas the authentic pair has a more rounded profile.
Example (click to enlarge):
When looking down on the shoes it is apparent that the real shoes have a more pointed shape, in comparison the the more rounded toe of the fakes. And, the stitching at the base of the tongue is lower on the authentic pair.
Example (click to enlarge):
The zipper on the back of the pocket should be silver, not golden. If you enlarge the image above you can also see the difference in the zipper toggle. However, not all of the fakes have gold zippers. Some do have silver ones.
Example (click to enlarge):
The above example shoes how many of the fake straps vary from the authentic ones. The fakes are slightly wider with a narrower fabric edge. It also appears that the hi-top part of this fake is straight, instead of at an angle like the real ones.
Example (click to enlarge):
Some of the fake versions of these shoes are made without the double tongue (but be aware that there are better fakes that have the double tongue). The authentic 'Astro' shoes have two tongues that attach together with a rectangular patch of Velcro at the top. The fake above is stitched wrong, with a half-inch between the stitching and the edge of the tongue. The fakes I've seen that do have the double tongue have more rounded corners on the outer tongue than the relatively squared corners of the authentic shoes.
Example (click to enlarge):
Here is an example of what the inside of the tongue should look like. Below that is a photo of the embossed "Raf Simons" logo that should be stamped on the insole of the shoe.
Example (click to enlarge):
Lastly, check the box. If the box is fake, chances are the shoes are fake too. The Raf Simons box should be a dark gray color made out of a flat cardboard (not corrugated). It should have a small glossy black logo on each end, and it should be blank on the top, bottom and other two sides.