Something like a devotion or a one page reading from AA literature or Sarah Ban Breathnach's, Simple Abundance.
The reading should ideally be between five and ten minutes long. Just long enough to engage your thoughts and set your attitude on a good path.
For people trying to read something longer like the Miracle Morning by Hal Elrod, or Tony Robbins' Awaken the Giant Within, the chapters are not read in five minutes, so it is necessary to break the chapters into smaller bits. You'll have to track your progress in the chaper somehow. It will be necessary to mark where you ended your daily reading.
Speaking of marking, you should have a highlighter handy, along with a pen. Highlight the passages, or fragments or anything you read that jumps off the page at you. It might be a sentence or a phrase. It may give you an "aha" moment or be something that just strikes you as being very wise, or something the is apropos to a situation or problem you are working with. Use the highlighter to make that phraseology stand out, and then use the pen and write in the margin the date that this particular topic leapt off the page into your conscious. It is a great tool for tracking those "aha" moments. Additionally, if you find yourself rereading the same piece at a later date, different things may hit you. Different times, different problems, different advise.
I'm here to tell you that it is okay to write in books. College students would not be able to survive their course load without using a highlighter and making notes in their textbooks. They have to do it all the time as a necessary practice. Students need to distill information and break it into relevant pieces so they can own the knowledge. With inspirational and motivating books, the authors are sharing knowledge that you, too, want to own and use.
There is a caveat. The only exception I would be inclined to make regarding highlighting and notating what I read is when I am reading is to know what I am reading. Am I reading a first edition hard bound copy of Think and Grow Rich? If so, I wouldn't write in it. That is valuable. Family heirlooms, like a gilt-edged family Bible - definitely off limits. Know what you are reading and if it has an intrinsic value either historically or to an owner or a family.
With the thousands and thousands of books printed today, you can probably find a copy that is not worth much in the way of family or historical value. This idea of damaging books dates back to a time when books were hard to come by and highly prized. Books like Think and Grow Rich are still being published today despite originating in the early part of the 20th century. I recently purchased a new copy of Think and Grow Rich on the $5 table at Barnes and Noble.
Some books to consider for your inspirational and motivational reading are:
Think and Grow Rich by Napoleon Hill
Outwitting the Devil by Napoleon Hill
Napoleon Hill's Greatest Speeches by Napoleon Hill
The Road Less Traveled by Dr. M. Scott Peck
The Last Lecture by Randy Rausch
Originals: How Non-Conformists Change the World by Adam Grant
The Code of the Extraordinary Mind by Vishan Lakhiani
Smarter, Faster, Better by Charles Duhigg
On Fire: The 7 Choices to Ignite a Radically Inspired Life by John O'Leary
Awakening the Giant Within by Tony Robbins
The Artist's Way by Julia Cameron
212 The Extra Degree by Sam Parker and Mac Anderson
Tools of Titans by Tim Ferris
Cirque du Soleil: The Spark: Ignighting the Creative Fire That Lives Within Us All by John Bacon and Lyn Heward
And books by Ken Blanchard, Brendon Burchard, Stephen Covey, Spenser Johnson, Suze Orman, Zig Ziglar, and Dave Ramsey (and a whole lot more!)
And if you really, truly can't find the time to read, make double use of your drive time by listening to these authors via audio books!