Agree with some great advice by OPs here already:
a) Complete spare set of "essential stuff" that you can lift and shift for travel in hand-baggage (make up, travel toiletries, chargers, headphones, annual insurance doc, passport, medication , and one "emergency" outfit, lightest possible top and trousers for example, doesn't have to be glam, just has to see you through the day if they lose your luggage, which, at some point, they will)
b) The person who lays out their clothes and stuff the night before wins
c) The person who has a paper back up of the travelling arrangements also wins.
d) Not sure of your expense system, but do it immediately if it is electronic, if not a folder for your receipts, and then do it on the way home. You are not their bank. Similarly do not neglect admin (timesheets etc.)
e) If you are career minded, spend time every working week on your own career - and I would recommend 10% - whether this means assessing what you have done, and getting the credit for it, training, looking at the job market or internal market, working out your next move or who to network with, thinking about how things could have been better, what you would change etc. Knowing the rules for promotion. Discovering opportunities. There are plenty that would say "That's not really on, I just want to do a good job and be loyal / brilliant at my job" and then work their fingers to the bone, only to have others who have been more savvy, but less skilled or hard working, step right on ahead in front of them.
f) Make many friends, trust few, always paddle your own canoe
Hope this lot helps, fab you are looking forward to Day 1 and good luck xx