[Aquarian Sports Cards]

And even the borders on that example aren't exactly oversized. It's probably fine, but still seems a little light top to bottom, and I'd take a really close look at that bottom border. There are variations in the cuts on these to be sure, but if you don't recognize what a somewhat standard amount of border is you're doomed.

To me the quickest way to make a judgement is what I alluded to above. Don't worry about does one border look small, worry about the combined size of parallel borders.

A corollary to that is don't worry about an angled cut as long as the cut is parallel. If the top cut runs up and to the right compared to the frame of the image than the bottom should also. That just means the sheet wasn't squared up properly when it was cut. But if one border runs up and to the right and the parallel border is square...