For most people, hiking is like fine dining: It's a pleasure best enjoyed in good company. But if you crave the singular adventure of hiking alone-the sense of absolute solitude and self-reliance, the mental challenge, and the silence--safety becomes a paramount concern.
Be realistic about your abilities. Stay within comfortable limits for mileage, elevation gain, navigational challenges, and technical skills. This is not the time to experiment with off-trail navigation or exposed scrambling. It doesn't have to be hairball to be enjoyable.
Hike In Familiar Conditions
Know the environment you are entering, its hazards, and how to travel safely through it. Don't make your first multiday winter trip or your first dry, desert trek a solo affair; build up a solid base of experience with partners like http://www.meetup.com/www-welove2hike-com/ before attempting an ambitious trip alone.
Whether you're an expert or a novice, going alone invites greater risk: HELP is not guaranteed. Decide what to bring--like a sleeping bag on a long dayhike--by weighing the consequences of not having it against the burden of carrying too much. Extra food, water, and a signaling device (a whistle, signal mirror, or cell phone) are musts.
Make Conservative Decisions
Before taking even routine risks (like crossing a moderately challenging stream), evaluate the potential dangers. Never rule out an alternative route or simply retreating. As they say, pride goeth before a fall.
Give your itinerary--including alternative, emergency routes--to someone who knows what to do if you don't return on time, but who won't panic and report you missing if you're only a few hours late.