There are many mistakes that first time cryptocurrency investors make, some of the mistakes will be highlighted below.

Firstly, By not securing wallet password or passphrase. Some newbies don't save their passphrase in somewhere save, some do save it on their phone notebook which the phone or computer might be stolen. This should be written In a book and have a duplicate somewhere and also save it to your email. As the password can't be recovered when forgot or lost.

Secondly, most newbies do look for a shortcut to earn coins. For example, some scammers might set up a website for bitcoin mining which will ask for the wallet details and after they filled their details, those scammer will just login and send his coin to their account. This personally happened to my friend on steemit the guy claimed to give them 500followers and 10SBD after login with their username and password on his website, after he did so all his SBD and Steel were transferred that day.

Thirdly, newbies don't do research on the coin that they want to invest in it before they put their money on it.