Choose a VERY long passphrase. For example, combine uncommon words like this:

unconventional blueberry unlike any other
semi automated shiseido mask
icelanders prefer real sauna

Combinations like that are memorable, easy to type and the most secure.

In contrast, pass phrases like @ut0m4t3d, Honey167! or lA45pf8$d are a poor choice when it comes to security. Because they are so short, on a fleet of 10,000 ordinary computers, these can be guessed in 7 seconds.

To read more, see zxcvbn article by Dropbox.