How to pick a good password
Traditional recommendations for picking passwords are to mix alphabetical characters, numerical characters, symbols, and character case. However realistically the biggest factor in the ability for your password to be brute forced or otherwise compromised is to increase the length.
The best choice for a strong password that is easy to remember, but hard to guess, is to create a passphrase which contains multiple short words which have no relation to each other, then sprinkle in a number, symbol, or upper case letter (you don't need to do all of these).
Passphrases with lengths above 15 characters are considered good, with a recommendation of passphrases exceed 25 characters where possible.