The main problem of safe password is problem of remembering. I do not think there are a lot of people who can remember all these expressions like @ivrC8#4u_B8. So, maybe, each of us remember from school poems that facilitate learning difficult rules. We can apply such a principle to memorize a strong password, don't we?
Let's generate some passwords and choose from them one, for which we are able to imagine a good and not difficult phrase. For example, this:46v7or1hnWOW. I have gotten something very strange:46 villages, 7 oranges, 1 hamster, n and WOW (World of Warcraft). In fact, the phrase can be absolutely absurd, most important that you will be able to remember it.
We can choose another way, take random phrase or string from a poem and use it for making your safe password.
The first variant:password containing only the first letters of words. Storm has set the heavens scowling, whirling gusty blizzards wild. Let's take the main letters:shsthswgbw. But the password containing only letters is not safe, moreover, since only lower case is not reliable. Make it more difficult. For that let's add capital letters and punctuation. We will make like in Pushkin's poem for easy remembering:Shsths, Wgbw. Password has become better, but not enough. Now we will add special symbols and numbers. At the same time we will try to make sure that we are able to remember it. For example, we will use instead of verbs #, so, instead adjectives —*. Because this is the quote, we add «»in the begging and ending of it also. And, to complicate the task absolutely for hackers we will write 8 after the second letter. As result, we get:«S8##ths,W**w».
This password is a really safe and strong password because he has more 10 symbols, it contains letters both registers, numbers and special characters.
We can use another way of making phrase for strong password. We take the first part of the phrase known us and get not safe password:stormhassettheheavensscowling. Then we start to «conjure». We replace a couple of letters with special symbols. At the same time we pay attention that similar symbols (a like @, n/№, s/$) are traced by hacker programs for a long time, and it is unreasonable to do similar replacement. For safety let's add in our password some numbers (put them into places of "congestion"of vowels) and uppercase letters. We receive something similar:s8hst@Sw/5gb2w.