I just saw this thread and even if it's 2 months old it's still relevant.

The main mistakes that I think are the most common in the newbies from that article are:

-Mining bitcoins - I remember when I joined bitcoin I wanted to mine, and basically my laptop got overheated and i couldn't bare the noise and eventually, my laptop just died and had to get it repaired. Got literally 0 from that.

- Trading altcoins, buying into shitcoins - I bought into a coin called Zetacoin because there was such a big hype over at cryptsy at the time. In the end it was near worthless, and i'm not even sure that people have exchanges for it.

- Buying coin with paypal/CC - The reason why people charge outrageous rates is because they have to assume that you are a scammer. If you are legit then you can always go through the process of verification and buy from Coinbase, or other big exchanges for close to 1% of spot price.