Caveat Emptor

I have not dated in 32 years.  Internet dating is a new frontier for me, one I am braving with excitement and trepidation.  It's a tool and I've learned a few things about using it wisely.
I've tried 3 websites.  One was paid, 2 were free.  I met a conman on the paid site and on one of the free sites so paying for a membership did not weed out scam artists. 
Here are some of the things I've learned.  When you write your profile you can't make it too generic or vague or you won't attract anyone.  But carefully read any responses you get.  I found men who parroted back to me the qualities I said I was looking for.  I allowed myself to be set up.  In giving them a very specific wish list I also gave them a script to follow.
Anyone who has trouble with the English language is a red flag.  Not an immediate delete but a sign to proceed with caution.  He could be in another country and trying to pose as an american.
Stay local!  It's easier to verify someone who's within 25 miles than at the other end of the state or even out of state.  Many men will say willing to relocate, distance no problem.  Distance will be a problem.  If you can't easily see someone 2x a week you won't be able to build a relationship.  That's the best case scenario.  The worst case scenario is they're scamming you and too far away for you to verify anything they tell you in person.
Be suspicious of anyone who travels out of the country frequently.
Don't be too quick to give out your email address.  You're more secure staying on the dating site.  If you do reach the point where you want to email someone get an email address that you use only for online dating. 
If someone tells you after a week or similarly ridiculously short time that he's sure you're the one, you're his future wife, etc., run.  He's days away from telling you he needs a loan.
If anyone asks you your mother's maiden name, run.
If he says he's a widow, find the spouse's obituary online.  If you can't find one, run.
Don't spend weeks emailing someone without meeting.  If you're at the point where you're emailing each other every day it's time to meet. 
If you are emailing someone off the dating website learn how to check an ip address.  One guy who told me he was in NJ was actually in Lagos.
Suspicion and cynicism will not make you appealing.  But too much trust will make you a target.  Trust but verify.   Ask yourself is there anything I've told him or he's told me that I would be embarassed to tell a friend?  If you can answer that yes you know you've overridden your instincts and it's time to run.  You may have allowed your desire for a relationship to overcome your common sense. 
The internet is a wonderful tool and can lead you to wonderful people.  Just remember that con artists also think it's a wonderful tool and can lead them to wonderful marks. 
Trust but verify!