Some basic important things you should check is as follow:

1) TRANSPORTATION
When you reached Bali Airport, what is next. Whether you just go to the taxi counter and ask them to driver you to your hotel, or you made a booking for a Bali car rental, and their staff has been waiting for you at arrival gate, and after that you can go directly to your hotel with your car rental?

Having a car rental in Bali you can go anywhere and anytime inside Bali island you would like, freely. Withour car rental, and just ride a taxi, it will very costly and it is not flexible to explore the island.

2) ACCOMODATION
Make sure sure booked for hotel before you leave for Bali. Maybe, you can avoid this step, and just show to a hotel to book a from. But, you hould do that in low season. Do not try to do that if it is under hogh season (July-August) and peak season NEW YEAR, as mostly there will be any room available. If there is, the price is not that cheap, or raised significantly.

3) EQUIPMENT
Do not to gring some basic stuffs with you, such as shower materiel, cloths, dark glasses, sun block, Bali map (or, Bali GPS), camera, hand book about Bali, etc.

If everything has been prepared as well, then you are ready for Bali!