Here is a list of things you need to carry when you go out on a Photo Trip:
Camera
It would be silly to mention a camera in the list as its the most obvious thing you will carry. But as its a list of essential things and camera being the important one, should be listed.
Lenses
Carrying a Telephoto lens on a photo trip to frame Tigers would be ideal, but don't miss out a macro lens if you love tiny creatures.
Batteries and a Charger
Cameras consume a lot of power especially when you shoot videos. So always carry an extra set of batteries and a charger.
Tripod
If you're a perfectionist and want your photos to be sharp and clean, then don't miss out a tripod. Its a handy tool when shooting landscapes and will help bring the noise factor. Camera shake is a common factor, so carrying a tripod is always a good idea. Professional photographers often carry tripods while on a photo trip.
Memory cards
Nobody would like to miss that perfect shot just by running out of memory. Carrying an extra memory card will not only let you capture that perfect shot but more no. of them without any hassle. A laptop can be used to store your images.
Other accessories
A flash unit is useful in getting better textures and a detailed photo. UV filters and polarizing filters are other options and will give you better photos.
A Camera bag
Keep your equipments safe and arrange them systematically in this bag. This also an obvious choice to have on a photo trip.
You don't have to buy all these expensive equipments if you don't have or can't afford them. First develop your skills, learn everything about photography. Initially you don't have to waste your money on them. Don't forget that you need to be good photographer to capture good images. Expensive equipments are there to make photography easier, that's it.
Carry gears that you think will be useful during your photo trip, try to keep it minimal. It will ensure that the weight doesn't distract you from focusing on your subject.