Brute Force and Dictionary attacks attempt to create a password that generates the same hash as your actual password.
Rainbow Tables work in reverse. They look at the hash and then attempt to generate a password.
This link gives good background;http://en.wikipedia.org/wiki/Rainbow_table
how do i check what hash is created by my password??
Don't worry about that, just make your password strong.
To make it strong don't use words or names.
Do make it long, mix upper and lower case and include digits and other special characters.
That of course makes it difficult to remember your password!
To get round that a good strategy is to use a phrase that you can remember easily then change and add characters. For example you might use a line of poetry, a book title, or a film title.
e.g. you might start with "Autumn season of mist" and create the password "Autumn_5ea50n_0f_m15t#"
Another strategy is to hide your password in plain view, for example "emw122AE!!" is my monitor model written backwards with a couple of exclamations on the end. It cannot be cracked by a Dictionary attack as it is not word based, and it would be difficult to Brute Force because it a resonably long alphanumeric with upper and lower case and special characters. At the same time I could easily remember it because it is more or less written right in front of me.
use the same password on several sites. A site owner may well be able to see your password in plaintext. Once somebody knows your password for one site they will try it on others e.g. gmail, twitter, facebook.
Identity theft is a bit different from getting your password. Keep your personal information private. You can give madeup info to sites as long as you keep a record of what you gave