1) Scott Adams 'How to fail at almost everything' for life strategy.
2) Robert Glover's 'No more Mr Nice Guy' for assertiveness and being your authentic self no matter what.
3) As cliche as it is, 'The Power of Now' is a great source to return to in times of personal and professional woes.
Good luck and Godspeed in your career(s).
I remember years ago complaining to someone that the manager of a project whose code I needed kept refusing to fix the showstopping bugs in it. His answer was "go over his head to his manager. No more Mr Nice Guy."
I thought it over and he was right: I'd tried being reasonable for as long as I could and this guy was preventing me from doing my job properly. I spoke to his manager (who I had a great relationship with BTW) and the problem was fixed literally within minutes.
Since then I've taken that approach to heart: either work with me or get the hell out of my way because I won't be held back.
The author isn't recommending anybody to be a jerk, but his admonitions to being more forthright, up-front, and a bit less scheming will help people find balance. And in consequence actually treating people with respect rather than project a somewhat false "nice-guy" facade.
I tried reading The Power of Now but sometimes I felt it became really mumbo jumbo with all the spirituality. Would you advise me to just power through it?
But for me it first took about two years of study into Zen Buddhism and easing into the 'spiritual' terminology and things like 'meditation'. Tolle can be a bit of a leap if you're not already comfortable with mumbo jumbo (even if it's mostly style and has real substance underneath).