The 27-year-old received some criticism for his performances during the winter tour of South Africa, where he scored just one half-century from eight innings.
However, while wickets fell around him at regular intervals, Hales responded on day one at Headingley to finish unbeaten on 71 from 154 deliveries.
Asked by Sky Sports News if he had intentionally made any adjustments during the break, the right-hander replied: "I've tweaked a couple of things, just outside off-stump. I think in South Africa a couple of times I maybe got caught between defence and attack.
"It's something I've been working on, but it's still a work in progress and I think it's going to be key to me being successful as a Test player.
"Throughout the Test series against South Africa, I didn't feel out of my depth - and I kept that in my mind. I think it was me making mistakes, rather than balls getting me out. I'd rather it was that way, knowing it was up to me to correct a few things."
Hales will return tomorrow alongside Jonny Bairstow (54) with England on 171-5.