There have recently been a number of news reports about hikers dying on hiking trails for various reasons - or needing to be rescued. Don't think of going for a hike as simply going for a walk. It's an activity that requires planning and preparation - even if it's just a day hike in a nearby park. Please follow the guidelines below and feel free to suggest your own at the bottom of the page.
Research the trail. Before going on a hike read up on the trail to get a sense of the terrain, duration, degree of difficulty and whether there are any particular warnings on the trail. There are so many good hiking books out there and I have yet to google a trail that came back with 0 results. Forewarned is forearmed!
Tell someone where you're going. Tell a friend what trail you'll be hiking, what time you're leaving and when you expect to be back. Check in if you're able to and let them know if you're on time or running late. There are also excellent groups like MountainSafety that track hiking groups while they are out on trails.
Don't hike alone. It doesn't matter it's a trail you've done a hundred times before. Freak accidents can happen - even slipping on wet grass with a backpack on can easily lead to a more serious injury and if you're with someone they can get help to you faster. Unfortunately, depending on where you hike, hiking is also not as safe as it used to be, with solo hikers often the target of mountain muggers. There's safety in numbers.
Watch the weather. Twenty years ago you had to try and catch a static weather forecast on TV or copy it from the newspaper and then keep an eye on the sky and hope for the best. Fortunately with the internet today there's no excuse for not getting up to the minute weather information for your location. Almost dying of hypothermia is not fun. Trust me - I can vouch for that one.
Gear up. Always take the essentials with you - enough water, sun screen, food, a basic medical kit, warm clothing. I have different kits for different types of hiking trails (desert vs mountain vs forest) degrees of difficulty and length of trail. Here's a excellent article by OutThereColorado about packing a daypack.
Wear the right shoes. Great tennis shoes are great for tennis. Great running shoes are great for running. Both are really comfortable and neither are suitable for hiking. I've seen a number of hikers have really nasty slips because they were not wearing dedicated hiking footwear. A decent pair of hiking shoes or boots can set you back as much as a good backpack - but are totally worth it. Walking over mountains, through rocky ravines, mud, water, sludge, deep sand - you name it puts a lot of strain on your feet and non hiking shoes simply can't take the strain and don't give your feet the protection they need - specially over longer trails. Few things are more disheartening to a hiker after a hard days hike than taking their shoes off and seeing blisters on their heels. I have a pair of hiking shoes and boots that only come out the garage for trails - not day to day use - and both are still in excellent shape.
Rest often. Fatigue can be a hiker's worst enemy - specially on technically challenging trails. Once you get too tired you starting losing focus and don't concentrate on where you're putting your feet. I saw a hiker fracture their ankle that way. Rather stop more often, rest and spend more time enjoying the scenery - that's the main reason you're out o the trail any way, right?
If you have some more ideas on how to stay safe on hiking trails please add them in the comments below.