Different approaches are needed in different regions, so the advice I offer here is geared toward the eastern and midwestern regions of the United States, but may prove useful in other areas of similar climate.

• Large, flat objects are especially attractive to a large variety of snakes. These are also ideal for the collector because they can be lifted without too much effort. Another benefit, is the objects are unlikely to be dropped upon the reptiles under them. I aim for 2'x2' or larger pieces of tin or plywood.
• Flat rocks are a useful alternative where they naturally occur in large numbers.
• Do not attempt to lift rocks too bulky to be turned over completely as it may result in a smashed snake.
• Hooks can be used to lift many artificial materials, but rocks will simply slip off injuring whatever hides underneath them. You'll need to use your hands for flipping rocks. The good news is in all the thousands, maybe even tens of thousands of rocks I've flipped by hand, the only injuries that ever happened were a result of insects, never a reptile.
• When the weather becomes too hot and dry for flipping to be effective, pit vipers can often be found  in crevices, so there is always something to look for outside of when it is simply too cold.
• Artificial cover objects will be most effective where they receive at least partial sun. I prefer open field or forest edges. Those placed in full shade are not as effective and less reliable.
• If you decide to collect a snake, make sure to check state and local laws first, as well as any rules for the specific property. If you are unsure of the legality, settle for a photo. Generally speaking, a captive bred and well started snake from a breeder will be a better bet. Simply return the cover object to its original position and turn the herps loose at the edge of it, head facing the object and it will crawl back in on its own.

Reading:
Some good books I can recommend on field herping:
Snake Hunting Guide by Will Bird and Phil Peak:  This is probably the best book on the subject for information on how to successfully get started field herping.
In Search of Reptiles and Amphibians by Richard Bartlett: This is a nice book that includes many tales of field herping from inside and outside of the USA.

Safety:
If you will be herping alone it may be worth getting a Satellite Communicator. This will allow you to send an SOS message with your coordinate should you get lost, injured, or bitten by a venomous snake. More practically, it will allow you to communicate with friends and family when you do not have cell phone service. Several brands are available, I recommend Zoleo as it is a good combination of reliability and cost. Another popular and reliable device is Garmin Inreach. I have heard mixed results regarding a couple of other low cost models and their reliability of obtaining signal when you need it. I would therefore recommend carefully checking reviews is choosing other, low cost devices.

Snake Hooks:
I do not find snake hooks useful for flipping rocks, and I have personally witnessed people injuring herps trying to do so as the rocks just slide off even with ones that have attempted to add some gripping to the hook. However, they are useful for lifting light sheets of tin and moving venomous snakes off the road. I use the titanium model as seen here.

Boots:
The choice of footwear is a tradeoff between how much protection you need, how quickly you need it to dry, and how much comfort you'd like. Snake boots are generally not the most comfortable to hike in, but they will hopefully offer some protection for your feet should a snake strike them. I do not generally wear them. but you can see a range of choices here. A good general purpose hiking boot is made by Merrell, see here. These are more comfortable than snake boots being more flexible and shorter and will still cover your foot so it will add some protection from thorns and rocks.