When your 2-year-old says no to everything, stop asking yes-or-no questions. Say "It's time to get in the car seat" instead of "Do you want to?" Or give them a choice between two things, like red cup or blue cup, so they can't just refuse.
Chapters
Great question about a 2-year-old saying no. So I'd say 2 things. One is just be careful of how you phrase your question. So you might say something like, "Do you want to get in the car seat?" I would just more likely just state it. "It's time to get in the car seat." And don't add "okay" on the end, which gives them the opportunity to say no. And secondly, give them a choice of 2 things. "Do you want the red cup?" or the blue cup, rather than, do you want a cup of water, to which they might say no. So hope that helps, and keep the questions coming, and follow me if you aren't already.