The only way you can prevent scams is if you know about them. There are lots of posts and groups that discuss scams you can help yourself by DYOR. Google can give you a list of scams and increase your knowledge if only you can create out time to bit that search button.
This is intact very true.
Firstly, scammers would stop at nothing even after several failed attempts, they'd still keep on trying and trying until they finally see that one naive victim that'll fall into their trap.
You're also right that the only way to easily detect these scams is if you know or have an idea about it, although not all scams are the same, but the common thing among these scams is that they're often too good to be true, they're often offering people free money and other similar ways too to identify them. The best thing is to always do your research so as to always stay ahead of these people, my thats the best way to avoid being victimised.