There are many books, magazine articles, and webpages with information on walks, day hikes, and backpacking. One book that I have found useful to read regarding day hiking is the following:
The Dayhiker's Handbook: An All-Terrain, All-Season Guide. By John Long and Michael Hodgson. Camden, Maine, Ragged Mountain Press, 1996. Index, appencices, 216 pages. ISBN: 0070291462. An excellent guide to preparing for and enjoying long day walks in the desert, mountains, jungles, canyons and streams, in the forest and along the coast. Practical tips and useful advice. VSCL.