Safety in the Field
Pack a First Aid Kit I recommend picking up a basic first aid kit at your local pharmacy or grocery store or creating your own. Anything could happen while you're in the field, and it's best to be prepared.
Wear Protective Clothing The most important item of clothing for a herper is going to be a pair of boots. Not only will they protect you from potential snakebites, they'll keep your feet and legs dry and you'll be happy to have them when you're trekking through mud and tall grass. Although you can invest in an expensive pair of Snake Boots like THESE, an inexpensive pair of rain boots are just as good. Choose something thick and sturdy with plenty of coverage and you'll be set.
Protect Your Skin It goes without saying, but it's always important to wear sunscreen if you're going to be spending the day under the sun. The only thing worse that a sunburn to spoil your day of herping is being covered in itchy bug bites...so don't forget the bug spray! Sunscreen and Insect repellent will be you're new best friends. Invest in them, use them, and bask in the glory of healthy burn-free & bite-free skin after a full day of herping :)
Hand Sanitizer Carry it and use it often. Just as important as protecting your own skin, it's essential to consider the lives of the wildlife you encounter. Some herpers handle animals they find, and some do not. It's a personal choice that you can make for yourself, but if you ARE going to handle an animal, be conscious of the health and well-being of the subject and it's environment.
Identification Research and know how to identify dangerous or venomous species in your area. Personally, I would recommend that you become thoroughly familiar with how to identify these species BEFORE your first herping adventure. If you're already herping on a regular basis and aren't 100% confident in your abilities to identify venomous species in your area, I highly recommend that you do so as soon as possible.
Flipping Safety When implementing the "flipping" technique of looking under rocks, logs, and debris, it is important to lift those items towards your body as opposed to away from it. This creates a barrier between your legs and a venomous snake, should their be one resting beneath the item you're having a peek under.
Cruising Safety When implementing the "cruising" technique, it is helpful to wear reflective clothing and keep a headlamp or flashlight so that motorists will be aware of your presence. Don't stop your vehicle in the middle of the road. Only pull over in a safe location so as to avoid accidents with other drivers.