Ask HN: How do I become a more focused reader?

I love reading. I have read hundreds of books in my life and I have hundreds more on my bookshelf (both physical and digital) waiting to be read. Lately however I've been finding it difficult to concentrate on reading for long stretches of time. I'll sit down to read and within 10 minutes my eyes will get heavy and I'll struggle to stay awake (even during the daytime). Other times, my mind will wander almost immediately. I'll be thinking about what's happening on Twitter or with my RSS feeds. Then I'll get halfway through a sentence and just stop so I can check social media. I'll set goals for myself to read, say, 50 pages per day but I hardly get through 10 and I'm already 'bored'. What are some practices for keeping my mind focused on the task at hand? I try to keep my phone in another room and set my Watch to do not disturb and that helps. But when I'm reading a book on my iPad, the home button is so easily accessible.