I'd like to address mostly the men here although the ladies may find this useful too.
1st is the picture. Who gets glamour shots anyway? If she looks to good to be true she's probably a fake. Look for selfies and more than one pic in different clothing.
2nd. Vague or short descriptions. While it's not bad to have a short intro, that should raise an internal alert. Most people like to say something about themselves to try and stand out.
3rd. What they are seeking. And please don't get me wrong but almost 99% of the catfish I see are seeking LTR or soulmates. It's a plot to get information from you.
Above all go with your own instincts. Don't give out personal info and enjoy this sight. We can't let a few bad apples spoil the fun that can be had here.