My constant companion when I am reading is my smartphone. When I come across a word I don't know, or one that I am not one hundred percent sure I own, I will look it up in an online dictionary before I continue on. Then I'll put it on a list on my phone.
When I get a few spare moments I'll transfer all the words to a book and add the definition. I don't copy the dictionary exactly and I'll add notes about how it was used to help me remember it.
Thanks for reading for V day, we're almost done! Tell me your favorite word in the comments.