Choosing to pursue an MBA means you've already recognized the need for self-improvement. An MBA creates new opportunity, and it's up to you to maximize them. Here are some of my favorite personal success books.
The most effective marketers at my firm are those that believe: "Know thyself". Strengthsfinder and Finding Your Flow are based on knowing your strengths and doubling down on them. While the mantra of "you can be anything" is certainly ingrained in our culture, the most successful businesses develop their core strengths and keep a bare minimum of other functions in-house.
Putting new knowledge in practice can be tricky. Proponents of the power of attraction (also known as The Secret) repeat the phrase. "figure out exactly what you want, find out how to get it, and be flexible enough to do that." The first two parts are easy. Changing yourself to enable the third part is tougher. Srikumar Rao delivers a course at Columbia University's Business School called The Personal Mastery Program. It's an amazing audio lecture that synthesizes ancient knowledge and modern psychology to deliver powerful productivity messages. Remember, "What Got You Here Won't Get You There". (That one's a good book too.)
My current read is an old one: The Now Habit, which traces procrastination to a few simple fears. The book shows how to change the procrastinator's self-talk to the producer's self-talk. Going a little bit deeper, Wayne Dyer's Excuses Begone is a deep dive to living consciously. Something is Sold" are reminders of the hard realities of business.
Success naturally follows; Dyer often quotes modern productivity speakers like Zig Ziglar and Anthony Robbins.
For those preferring a firm approach, check out It's Called Work For A Reason by Larry Winget. The "Pitbull of Personal Development", Winget strips away pretense and reminds us of the realities of the business world.