If you reenter the same password correctly, you will be told that all authentication tokens were updated. It is important that you select a password which will be difficult to guess or generate from a list of known words. This can be used for performing spelling checks on your system, but it can also be used by crackers to for guessing passwords. Your paranoia level should be driven by your real security needs. A good password will contain a mixture of from eight to twelve alpha-numeric characters and punctuation marks.
Random strings are best, but are difficult to remember.
Try generating a password string from a sentence or phrase. An example would be mvemjsunp . This is actually a poor suggestion since it is a fairly well known mnemonic device, but it illustrates a useful technique for generating easily remembered passwords. Now that you have a non-root account, you will want to use this account almost exclusively. It is very easy to make a silly mistake on the command line.