Lately people have been coming up to me in the CS lab asking about how I manage to remember my really long password(not necessary but I'm paranoid) which is 24 characters long, alpha-numerical.

So for whoever is interested, what follows is a really short guide on how to create the "perfect" password.

If you're like me you probably don't have the same password for every single thing but you probably have about 3-4 passwords you tend to use for different things be it email, ftp, forums, etc. Having the same password for everything is generally a bad idea. What follows is a hypothetical situation:
Let's just say you use the same password for everything your email, your main FTP for your website, your work login, SSH, etc. One day you find a new forum that seems interesting, so you sign up using the password you use for everything else, but unbeknownst to you, their users passwords don't have any sort of one way encryption such as MD5. A few days later you notice you can't login to your email, or FTP. A hacker has exploited the forum and downloaded a copy of the user table from the forum which he then went through checking if these unencrypted passwords are used elsewhere, naturally you probably put your website URL in while filling out your user profile so it's obvious that the hackers going to check that first, followed by your email address.

Though the latter situation is probably unlikely since most forums have some sort of encryption going on(usually MD5) for the passwords it's still very possible for them to do a brute force attack on those hashes with a large enough dictionary, or quite simply you could have a crooked forum admin who decides to take off the encryption.

So, what's the best way to avoid all this? Use different passwords for things with varying levels of importance. Let's say your forum logins are at the bottom of the list, use a common password for those, next up your website use a common password for that, and your email, etc. Not necessarily full proof, but it gives you a bit more damage control. If someone manages to grab your forum password, that's all it'll be good for, other forums.

What if you want a very strong(long) password but have the memory of a fish(like me)? Gather the list of all your commonly used passwords, then arrange them in a certain order.
For example if all the passwords you knew and used were
asfrt4
783hf7
343fjj
39famc

Then you simply combine them in to one, all you need to know is the order:
asfrt4783hf7343fjj39famc
there you go, an insanely long password...that could survive most(if not all) brute force attacks. As long as you remember the order that your common passwords go in then you're good to go ;). Of course if you want to you can add extra variation by using the first 3 password in order then using the 4th's characters at every 3 characters or so, whatever works for you.

In conclusion, this technique should make it very easy for you to make and remember a long set of letters and numbers, of course, if you already have really weak passwords to begin with then...well..reconsider..if your end result is something like
1234passwordcalifornialol
then you should probably get your self a new set of commonly used passwords.

Hope that wasn't too lengthy, obvious or boring but maybe that'll help someone.