I usually read a few pages of a book or a news article, whenever I look up a word I either make a card right away or I will mark the word (e.g. in my ebook reader) to make the card later.
I think the biggest plus is making the cards yourself and not using pre-made. It's work, but it seems to be worth it. #anki
In two month, I created around 1450 cards, about half are mirror cards to learn something two ways. Around 900 of them are what #Anki considers "mature", meaning I know them quite well and remembered them in reviews.
When I first started out I almost put it away immediately because you don't have to type the solution (although Anki has this as an option too as I later found out). It was a bit unusual for me that I have to "supervise" myself. But guess what, I'm not in school, I do this for fun, it's not a test. I want to remember the words when I need them and I want to recognize the words when I hear/read them. Not typing is absolutely fine and you can work through the deck much faster.