Evenings are getting warmer and longer, but you can kick back only if you aren’t at the office.

The bad news is your to-do list may dismantle your sunset-watching desires. But fortunately there’s good news. Andy Core has some work-smarter ideas to help you get home at a reasonable hour so that you can enjoy those warm summer nights.

The author of the new book “Change Your Day, Not Your Life: A Realistic Guide to Sustained Motivation, More Productivity, and the Art of Working Well” www.andycore.com, promises to help you become what he calls a “Thriver” — someone who works hard, meets or exceeds expectations, and enjoys high levels of personal and professional success, accompanied by (and this is the best part) lower stress levels.

Here is one of his strategies to help you change the way you approach your day—and get out of the office earlier:

Instead of adding to your to-do list, build a new pattern. Maybe you’re thinking, Sure, I’d like to change the way my days look, but wouldn’t that involve doing more than I already am? The thought of adding anything else to my already out-of-control to-do list makes me want to crawl back into bed. I can’t handle any more tasks and responsibilities! If that sounds familiar, take a deep breath. The changes that build momentum are rooted in decisions, not additional tasks.

“To build a productive new pattern into your life, you usually won’t have to add new tasks to your day,” Core confirms. “Instead, you’ll simply do what you are already doing, or want to do, in a way that becomes habitual. For instance, if you want to wake up an hour earlier so that you can jump-start the day, you simply have to change the time your alarm rings and the time you go to bed. If you want to be more productive at work, you might have to replace aimless procrastination with scheduled breaks. In both cases, you’re changing the way you perform existing tasks, not adding new ones.

“Remember, though, it isn’t sufficient to simply trigger the start of a new behavior,” he adds. “You need to make sure that you have a motivating reason to make this change—like being able to enjoy evenings with your family—as well as the confidence and energy to sustain it so that it becomes a pattern.”