I'm not saying that's how you should ALWAYS write a poem. Some poems, usually short ones, just come to you - often from chance things happening to you; others you start off having no clue why you are writing what you write and the meaning and purpose become clear later; yet others you might start off writing the ending (I often do that).
Also, just because you think about what you are going to write and write a short prose plan beforehand, it doesn't mean you have to stick to it. Maybe when you start to write the poem will veer off in an entirely different direction.
The reason I'm suggesting that you plan this one is firstly that I suspect a good villanelle was never written without some planning, and second it will do you good to write in a different way to the way you usually do. Believe me, there is no such thing as experimenting too much when you are learning how to write. It's all good practice, and if you don't try it you'll never know.
Now what's this villanelle going to be about? Remember what I asked you to try to do? Emulate DT and EB - try and move from the general to the specific. Perhaps some general stanzas about an aspect of human behaviour, and then finishing by zooming in on how that behaviour has affected you personally. The behaviour could be things like, love, betrayal, dishonesty, kindness etc etc ... anyway I don't want to distract you with my ideas, you must try and figure something out yourself.
Have a good evening.
PS When I said "you personally" I mean of course the speaker in the poem. The speaker doesn't have to be you, and even if the speaker is the first person (I) you don't have to tell the truth as long as you tell the truth! What I mean is you can of course make things up provided you are true to your feelings. I think I've confused you enough for one day.