A good photographer has to plan their day carefully, taking a camera with you is usually not enough. Through experience I have accumulated a collection of things that can come handy, and keep in mind that every location has its own set of requirements. I will walk you through the basics and tell you what I personally carry.
Cameras come in different sizes and each one has unique characteristics. You need fast autofocus if you are into sports or wildlife photography. While night time photography generally goes better the larger the sensor is. I have three different cameras, each one with its own purpose.
A good camera needs to be paired with an equally good lens to show its true potential. No lens can do everything, which is why you should have multiple ones. A lens with long focal length is needed in wildlife photography, because you can often times not get close enough to the animals before they run away. For landscapes you want a shorter focal length to fit more into the frame. These are the lenses I have at my disposal.
There are many things that can make your trip both easier and more successful. The exact arsenal of tools is individual and you can not carry everything at all times. Read about the location before you go there to learn about the weather conditions and potential dangers. These are some of the more commonly used accessories that I have.