The easiest way to stop the baby feeling discomfort from the pressure changes during take off and landing is to feed her.
The swallowing action naturally equalises the inner ear pressure and she shouldn't feel any pain.
You can do this either by bottle or BFing. Whichever you normally do. Don't worry about BFing on a plane. No one will have a problem if you do it subtly.
There is little chance of her vomiting. I wouldn't worry about that too much. If she does vomit, just deal with it as you normally would on the ground.
Most people advise trying to change to the new time zone a day or so before leaving and certainly while on the plane. On the other hand, it depends how long you will be there for. If it's a short trip, you might prefer to leave her on UK time througout the trip...
Stuff to carry for the baby, would include formula etc if you use it, a good supply of nappies, some snacks if appropriate, some toys to entertain her, a change of clothes.
Depending on the airline, they will give you a baby meal for her on board if you order it, they may also have some nappies and toys, but don't rely on those.
Depending on her length and weight, you may be able to book a bassinet on board for her to sleep in. Depending on the airline, they are usually available to babies up to about 75cm, 10 kgs and 1 year old. They are really helpful and can be booked for free. Book it when you book your own ticket.
I would also advise taking a sling of some sort. If you will be travelling alone, you will spend a lot of time carrying both your DD and all your hand luggage around the airport. It's tiring.