A few triggers can help you:

1. It's an ICO? 100% scam
2. It's premined? 100% scam
3. It's not minable? 100% scam
4. It's a clone of another coin? 90% scam

Hope this helps and I also hope you guys have some brains to choose a few nice, fair, decentralized coin to invest your money and not all those shitcoins.