Everyone prepares for a trip differently. While some people like to procrastinate and wait til the last possible second to even start packing, I prefer to begin preparing much further in advance. A lot of this probably comes from me thinking I am going to forget something, and that would be a pain in the ass while traveling abroad, so I try to get ready ahead of time, knowing that life really can get in the way of preparing last second, especially since I will usually work right up until I have to head for the airport.
MAKE A TO-DO LIST
This has to be my biggest item that I always seem to do. I must admit that my to-do lists can range from general to more intricate, and they don't always included everything that needs to get done, but it does cover a lot of the bases that I could miss otherwise. They usually include credit card information, not my numbers, but just ways for me to confirm where I have my copies, if I set travel notifications, and what the fee's are for my foreign fees. Nothing would be worse then leaving for a trip and getting locked out of your credit cards. The same thing goes for my passport, itinerary, and hotel information. I make a list of where the copies are and who has them just to confirm for myself.
As someone who drags along a backpack full of GoPro gear, theres even a checklist on my To-Do list for them. Ranging from serial numbers, to how many of everything I am bringing. This is partially because depending on where I am traveling too, or with who, for example my next trip to Europe, I am traveling with EF College Break, and don't know how long I will have to be charging devices, so my list is different then traveling with family to Italy, where I knew I would have more time to charge up devices, and knew where I would be staying. So my list for this trip includes more power banks and backup batteries, then my trip to Italy did.
For some of us, this is something that we already do, while others of us are still packing clothes on the way to the airport. My biggest tip is to pack clothes early. Maybe not everything, but anything that you are sure you are going to need, and won't need before your trip. Its a good way to gauge if you need a bigger bag for your trip, or gauge exactly what else you are going to need. You don't want to be packing last minute and find out that you forgot that you needed to buy socks, and you're almost out the door headed to the airport.
This also means that you need to be sure, or pretty sure, of what you are going to need for you trip. Check online resources to see what the weather usually is where you will be traveling at that time of year. You don't want to get caught without a rain jacket with daily afternoon rain showers when a simple online search would have told you to expect them. This is one reason why I always bring a lightweight NorthFace jacket with me, it came in handy in Costa Rica when we were supposed to be in the least rainy time of year, but always seemed to have showers.
The night before you leave, and the day you leave, can be the most stressful part of an entire trip. You don't want to make it worse by waking up and seeing that your phone has 10% battery and you're leaving in an hour. While some planes have charging ports these days (these airlines and planes deserve all the credit for being awesome) some don't. One of the best things to do is charge up all the electronics that you are bringing, and then put them away. While I know you probably won't be putting your phone away for the day, put away the cameras, iPads, and laptops for the day, and keep those batteries full. My tip is to make sure your phone is charging the entire time you are in the car on the way to the airport, that should at least get you to the airport with a full battery, or you might find yourself sitting on the ground next to an outlet in the terminal, and they are probably all already occupied.
GRAB SOME CASH
This might seem like a no brainer, but grab some local currency from your bank. The exchange rates are often better then exchanging currencies abroad, and saving some money is always a plus since its more you can spend on the trip. Having some cash with you is always a good idea for when you find places that do not accept credit cards or debit cards, and you will find those places at the least convenient time. So grab some cash and be prepared. I figure that I would like to have about $30USD per day on me if I can. For trips 5 days or more, I will usually bring along $200USD worth of local currency, since I can usually find an ATM somewhere in the first five days if I really do realize that I need more.
Now, obviously this might not work for everyone, because everyone prepares differently, so this is just to give people some ideas that they can adapt for themselves. You want to make getting ready for a trip to be easy and even fun, you don't want to stress out so much that you're still stressed when you arrive at your destination, that would ruin your trip. One tip that I really didnt mention was to check your destinations weather right before you go, so you can make any quick adjustments to your suitcase that might be needed. So get prepared, and have fun.