I would say that there are no 100% how to protect yourself from being scammed, but you can highly increase your protection and chances to avoid scam brokers by knowing their strategies and the most commmon characteristics. You can do this by reading detailed reviews on a specific scammers who are already know, for example you can read here about scam broker TriumphFX  https://globalfraudprotection.com/scam-recovery/triumphfx-broker-review/. It is  a good example of a fraud scam.