2017 BMW 118d F52 - Best way to mod for better MPG

I've recently acquired a 2017 BMW 118d F52 and I'm keen to squeeze out as much MPG as possible. Has anyone experimented with specific mods that yield noticeable improvements in fuel economy? Thinking along the lines of air filter upgrades, exhaust modifications, or perhaps some tuning tweaks - interested in hearing about any successes or failures from fellow owners!