I've been abroad a few times with Type 1.
You should get a letter from your diabetes clinic that says you need to carry needles and insulin with you to show the airport security if they ask any questions.
You should take all of your supplies on board with your in your hand luggage, don't check your insulin in with your luggage!!
Are you crossing time zones? If you are, find out how much hours in front or behind your destination is and you will need to adjust your basal insulin for the time difference.
It's up to you if you want to tell the airline that you are diabetic or not... They usually do a diabetic specific meal option, it all depends on what diet you follow. As a type 1, for me, i dont bother because i like to eat normal stuff. Having said that, the first time i told them my 'diabetic' meal was nicer than my other halfs non-diabetic meal!
Take more supplies than you need... it's always better to be safe than sorry.
Does your hotel have a fridge?
If you are going to a hot country like Egypt or something, i would recommend Frio pouches to store your insulin pens in while you are out and about, they're really good at keeping your insulin cool during the day.
That's all i can think of off the top of my head lol, Hope it's been of some use!