Modern password-cracking tools are quite good at obtaining credentials very quickly. Use a phrase, along with spaces, numbers and punctuation. Do not use words and phrases that are common knowledge. Pick something private and important to you, that is both easy to remember, but difficult to guess. Add some case variation. For example, "Fishing 4 trout, lake Mohawk." This password will take some time to type, but it is memorable and difficult to crack.