Essentially an izakaya is a Japanese tavern. But it's also Japanese tapas. And it's a Japanese gastropub. So perhaps the way to think of an izakaya is as a Japanese gastro-tapas-pub. Don't plan on having a 45 minute meal before a movie. Don't plan on going and having a starter, a main, and a dessert. Go planning on having a long, lingering meal over good drinks and better conversation with a group of great friends. Make an evening of it. Once you're in that mindset the rest is easy.