High achievers are typically keen on self-improvement. For me, that means constantly having a stack of books on my desk, bedside table, kitchen counter and in the door of my car which have been written by smart people. Here are several nuggets I've bookmarked in the last week in my quest to get better, achieve more and feel more fulfilled. If you're like me, these challenges serve as inspiration.

If you want to achieve more, you need to work harder than everyone else

In Rare Breed: A Guide to Success for the Defiant, Dangerous, and Different, Sunny Bonnell and Ashleigh Hansberger tell the story of Kobe Bryant addressing his fellow athletes while accepting the 2016 ESPY Icon Award, during which he refers to the kind of legendary and obsessive work ethic it takes to become great.

It's the same with you. The authors put it this way:

Most people won't do what it takes to be truly excellent in their field, but then they feel frustrated and demoralized by not being where they want. They won't work weekends. They'd rather party than study. They live for Fridays. They wouldn't dare show up two hours early for work to get a head start on a project. And they sure as hell aren't rolling out of bed in the middle of the night to shoot free throws.

How much harder are you willing to work, compared with the people around you?  

Never negotiate against yourself

It's called having a "poverty mentality," according to David Nichtern, author of Creativity, Spirituality and Making a Buck. He says that while there may be people in the world rooting for you to fail, falter and doubt yourself, that person should never be you. While it's important to possess an honest assessment of your own strengths and weaknesses, often people get into the habit of defeating themselves in the mind before undertaking anything.

Overcoming this tendency, he writes, necessitates taking control of your thought life and cultivating kindness and compassion toward yourself. "When we lack confidence, for whatever reason, we can easily underestimate our own value and the value of whatever it is that we're presenting as our offering," he writes. "Our business can only succeed to the level of success we'll allow in our life."

You must have a coach

Just like there are certain parts of your body you can't see when you look in a mirror, there are aspects of your personality and performance which elude your awareness. In Aligned: Connecting Your True Self With the Leader You're Meant to be, Hortense Le Gentil makes the point that just like elite athletes cannot become champions without a coach to develop their talents and provide motivation and emotional support, you need a coach in business, too. "The notion that everyone, including surgeons and CEOs, can stretch further and perform better, no matter how good they already are, is making headway outside the sporting world," he writes. "Studies have confirmed that coaching improves how individuals function in organizations, with significant positive effects on performance, skills, well-being, coping, work attitude, and goal-directed self-regulation."

Not sure how to find a coach? Another word in the business world is "mentor." Find one by identifying someone you respect and want to emulate. Then, figure out what you can offer them in trade for taking you under their wing. It's all about finding ways to create a mutually beneficial relationship.

Do what doesn't come naturally

In Elevate: An Essential Guide to Life, Joseph Deitch makes the excellent point that people tend to fine-tune their strengths instead of working on shortcomings and weaknesses. However, your productivity and profitability can be dramatically multiplied by doing the hard work of leaning into what you're not good at. Deitch writes:

Let's face it, focusing on areas of strength gives us pleasure, while dealing with our weaker attributes is usually unpleasant, often frustrating, and sometimes agonizing. As a result, we generally don't want to confront those weaknesses. Plus, sometimes we believe that we don't have to look at them because we're sufficiently successful doing what we do well, and we rationalized that we can just keep doing things the way we always have.

Not only does confronting weakness exponentially improve performance, it also bolsters your self-image. It's because you know deep down that your willingness to do hard things is what sets you apart from your competition.