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.
Its actually simple as that instead of giving your bitcoins to some scammer just hold it into your wallet and see your profits increase or if you are experienced in trading, you can trade crypto currencies and make some money or even when you lose it you lose it on your own volition instead of being tricked by someone.