In my years of experience with bitcoin there is only one effective way to avoid scammers. In joining ICO even if you do your research you will not know that they are scammers until the ICO is over. Even if how many preparations we do or make in the end we still end up being a victim to scammers. The best way to avoid scammers is to no invest your bitcoins. Just hold it in your wallet and hold it for a long time and when the price is right you can sell them and you will have a good profit.