This is how I normally do to identify scammers, with this; you should be ok for quite some time.
First :of all, I do Google search with the name of the company and the word scam. Normally, there should be no page with the company listed with the word scam next to them but if you see at least one, maybe it is a scam. No need to have several pages, only one is necessary.
Secondly: I go on a very good website, www.fraudwatchers.org that has a list of all website and company listed as scam. They just saved me from sending sample to a scam company.
And thirdly: just ask people around on forums just like this one. I saw a mate who has done that.
Fourth: steps are that you can verify the address they gave you and find out what’s really on this. Go on www.whitepages.com and enter the address they gave you to find out if the address is really registered as their business address or at least at their names.
Fifth test is to ask them to phone you. Normally scammers won’t do this but beware; some also tries to call you. Please be aware that some scammers uses call redirection which is call callback (I’m not sure of that) or they can use fax to email. Using this, they get number that are listed in U.S.A., U.K. or any European country where in reality, they are located elsewhere
Sixth: always inquire about the mail address. This is a mistake scammers often made. Try to see whether the email address comes from a free mail server..
Seventh: last advice for the time being; JUST COME AND ASK ME. Yes, you can come and ask me and I’ll help you. I’ve been for so much time victim of scammer, who fortunately failed in their attempts, that I’ve got some pretty much experience.
This is approximately all I can remember for the time being but again, if you need advices, feel free to contact me, it’s free