DO change your password regularly, preferable a couple times each year, once a quarter would be excellent. The above list may appear to limit passwords to an extreme degree, but it is possible to choose good passwords that obey all the above rules. Memory tricks are most useful in helping to choose good passwords. It is often possible to choose a line or two from a favorite old song or poem or book and select some letter sequence from it. These are all good passwords and relatively easy to remember.
Some people like to to use nonsense words.
If you are so linguistically inclined just alternate consonants and vowels and be creative. It is nice to get an uppercase letter or a number or punctuation mark in there also, preferably in the middle somewhere. Choosing two short words and concatenating them together with punctuation is quite good. You have the idea. If your current password isn't so hot, perhaps it's time to go invent another one.