Most common mistake of the newbie crypto investors is getting into the trap of the scammer pump telegram channels
Red flags are:
1) Ridicilous profits promise - trading without stop losses 667% profit per months?
Read here how they fool you: https://cryptocoinrankings.com/blog/index.php/2018/03/04/how-to-make-more-than-667-profit-in-cryptos-in-1-month/
2) Pump and dump schemes - check here why they never work
https://cryptocoinrankings.com/blog/index.php/2018/01/12/pumpdump-scams-how-they-fool-you/
3) Fake premium groups - most of them simply repost free signals and steal signals from reputable channels.
4) Clickbaits and cross-promos - usually filled with BS like "Satoshi nakamoto arrested" or "Ripple will grow 120000% tomorrow because of these news"...
5) Fake coins and scam icos with fake advisors
Here is the list of scam coins https://cryptocoinrankings.com/blog/index.php/2018/01/17/scam-coins-to-avoid/
6) Bitcoin Multipliers scams - it starts like "earn 0.5 btc per day for 30 days without investments" - remember there is no free cheese! Facebook is just filled with those. Avoid any FB group that starts with "Bitcoin" in its name.