Considerations
The fact that they are ectothermic is key to catching sightings. They can be found trying to soak up the heat energy from warm surfaces or sunlight.
Snakes will get defensive, but are not looking to chase you. Just give them a respectful amount of space. Animals will act how they will and its up to you to make the decision of giving them a respectful amount space to keep you and the animal safe.
In the united states the most amount of reptiles diversity can be found in the more arid regions, while amphibians can be found in moist or bodies of fresh water.
Tools
Some snake species are venomous so snake leg guards can be used in situations where you may be traveling through risky terrain. In the US this would mean arid habitat that may have a large amount of thick grass that makes it difficult to see exactly where you are putting your feet.
There are many good guide books that can help you identify species. These are typically organized by body morphology snake, lizard, turtle etc.