There are usually three types of romance scammer:
Vlads are from the former Soviet Union.
Lads are 419 scammers who also do love scams.
Pinays are from The Phillipines and are usually scam/beggars

Is it a Vlad or Lad or Pinay? Part 1 - Vlads.

Let's start with vlads. Vlads are scammers from the Former Soviet Union (FSU for short), and have some easy to spot signs. They're not 100% guaranteed, but a very good indicator.
Does the email address end in a number? Sometimes this can be telling. Vlads often use something like olga777@, while a lad will use jon4you@ or smithjames@ at the start of their email address, but sometimes will also use the number at the end. The best way to check, is the ip address used.
Look at the IP address the email came from. There are places that pop up time and again as being hotbeds of scammer activity. Mari-el for example. Also look for spoofed headers. Look for ones that show up as places like the USA or UK when they've said they live in Cheboksary, Russia.
The Bat!, Becky!, Voyager! mPOP or a similar x-mailer in the headers. These programs allow multiple accounts to be run at the same time off a single program. It's ideal for a tech savvy scammer to use.
The phrases they use. Here's an example 

Certainly, I cannot describe to you myself at once. I very simple person!
And I to speak all which I feel also, I do not hide anything from people. Unfortunately,
I have no any person whom I could love. I want to find suitable
The person for a life, also can be good the friend. I would like to care about
The person and to love it. I very simple person and I to not aspire to riches,
But I to aspire to the best conditions lives, actually, for this purpose it is necessary To live. I so think

The script they use has been run through translation software, and it leaves some very obvious phrases. "I very simple person" or "I the very simple person" for example. With practice you'll learn these and spot them easily. Google odd sounding phrases and see what turns up. Have a go with "i the decent and sociable girl"
Ignoring your emails, and sending out generic, scripted emails in reply. Ask them a question and watch it get ignored. Get thanked for a photo you never sent. Send them their own emails back and STILL get replies. It's pretty obvious the first lot of emails you're sending aren't being read.
Falling in love with you within 3 or 4 emails. Realistically, is that ever going to happen?
If the headers show Ukraine and the pictures look like a softcore porn model, then expect an email telling you that to continue talking to the girl you need to pay a translation company a fee for them to translate the emails between you and her. That's your typical Ukraine translation fee scam.
Pictures taken "just for you" that the EXIF data shows are old, maybe even years old.
If they phone you up, do they sound like they're reading from a script, or that there's no real passion in their voice? That's because the scammers pay girls a tiny amount to make phone calls or take photos. They sound like they're reading a script because that's exactly what they are doing. 95% of Russian romance scams are done by males, and the women in the photos are either innocent victims who've had their photos stolen or a girl paid to make personalised pictures. Don't let a pair of long legs distract you from what the person behind the words is trying to do.

Is it a Vlad or Lad or Pinay? Part 2 - Lads

Here's a typical lad profile

am,ligth in complx,brown eye,5 ft, am, so humble,respectful,calm,cool headed,good looking,loving,caring,and so many good all.i like to play basket ball,i like to dance,clubbin,reading,smiles,and share joke.

See the bad spelling, poor use of punctuation, starting a sentence with "am" instead of "I am". Other phrases that pop up are "Am John by name" or I was the only child of my parents". Again, in time you'll learn to spot these easily. Lads also have a poor concept of past and present tenses, often adding an "s" or "ed" to the end of words inappropriately.
Pictures are often stolen from modelling sites, porn sites or even real profiles on dating sites. Does the photo match what they claim about themselves?
Often they'll be "currently in (insert place here), but about to go to West Africa for business/charity work/a modelling assignment. This is to explain away why you'll need to send money to them in Nigeria further down the line.
Overuse of the <BUZZ> feature in IM chats. They say hello, and instantly <BUZZ> you.
Claiming to be an engineer/studying a degree, especially if coupled with very poor writing skills.
An email address ending with something like 2cool, 4luv, 4u, 2006, 001 is often seen with lads.
A name like Smith David or Davids Thomas, where the last name and first name are mixed up.
These are all signs to look for to identify your scammer as a lad.

Is it a Vlad or Lad or Pinay? Part 3 -Pinay

These are easy as they tell you where they're from and also appear on webcam so you can see they're really who they say they are. The only real complication is determining if it's a scammer, beggar or a cam girl.  The following is quoted from another scambaiter.
"They kind of cross lines between begging, scamming...and sometimes porn cam girl.
You'll have to be careful to provide evidence she's lying.
It's not really scamming to 'beg'.
That is the problem with the pinay scam/cam/beggars.
You can catch her in lies about what she needs money for....'I need money for nursing school', 'I need money for my mother's operation'
(but she said she was in school to be a teacher, and her mom died.....in another chat...get the drift?)
If she's begging for money, or strong hints....it's not really a scam.
If she LIES about the reasons needing the money....
"My father needs an operation!!" (he was dead last chat)
you can go all out.....
Strangely, 'begging' on chat seems to be a part time job a lot of people in the phils have. I've seen mom and daughter teams, aunt and niece, etc.
Sometimes you'll see an adult barely off cam coaching the younger person."