When giving a speech, which of the following is the best method: Memorizing the entire speech? Using an outline? or Using flashcards/notes?

I believe that memorizing is part of what you ought to do before doing a public speaking. What is more important is to have your ideas and your thoughts aligned, having small notes and of course an outline to have a perfect flow to your speech instead of rambling and jumping from topic to topic. 

Memorizing entire speech and also add your practical experience with that is a best way to convince the audience.