I've found it easier to pick fairly long quotes or text phrases that I can remember and convert them into passwords by using the first letter of each word. For instance, we'll take the standard "Every Good Boy Deserves Favor," which is a bit short but serves to illustrate the point.
It could start as egbdf and be semi-okay, but not complex enough.
We can do some numeric substitution to make it a bit tougher: 3gbdf
Then maybe mess with the case a bit: 3GBdF
Some punctuation to round it out: 3GBdF!
That's a dirt simple example, and you'd want longer and more complex phrases, but this helps you to create a complex password that's easy to remember and hard to break.