If you like to paint from reference photos, I would recommend a simple and free or cheap app for your phone/tablet, such as Artists Grid. Helps you freeze the lighting, which changes constantly outdoors, plus choose your composition and your value structure.
I generally paint directly from life, adjusting as I've learned how to do it, for the color temperature, the light changes and the air temperature. But that little program has really come in handy a few times, believe me.
David Dunlop, a terrific and prolific teaching landscape painter, has some of his fabulous videos on YouTube for free. The rest are a series you can purchase or occasionally find in reruns on PBS. Whether he does it actually in situ or in his studio, if you get his method and absorb his quick and cogent lessons in perception, you will be well prepared to face the outdoors with more confidence.
When I started painting many years ago, some of the best books I read were not your usual "follow my steps to this painting" kind. They were Faber Birren's books on color and other aspects of perception and how to create the illusion when you're painting. Invaluable. You might find them in a library.
Here's a page full of them on Amazon: https://www.amazon.com/Faber-Birren/...ne_cont_book_1
I realize this is a very different approach from just "how to paint" or famous artist inspirational books.