The first thing you need to decide is if you are coming back or not. If you know you are going to return to your home country at some point and then change your mind, it is a lot easier than if you decide you want to be a permanent resident of your host country, start the citizenship process and then change your mind. I would err on the side of assuming you are going home if you have any doubts. But if you have a decision in mind, the rest of the paperwork, packing up, and finances situation can be a lot more clear cut.
Be prepared for paperwork. Lots of paperwork. You’ll need a passport if you don’t have one already. You will likely need copies of your medical records and may need vaccinations depending on where you’re going. You will need a visa, a work permit, and possibly a new driver’s license. However, the rules and requirements for those are going to depend on where you are from and where you are going. If you plan on voting absentee, you’ll need to arrange that before you go as well. If you have already been hired by someone in your host country, ask to speak to human resources or see if they have a transition person. They will likely be able to walk you through the steps for everything you need. Do not assume they will do all the work for you to get all of your legal affairs in order!
You also have to make a big decision about most of your stuff. You have a few options: you can ship it all, which is expensive, probably unnecessary, and a giant pain; you can store whatever you don’t need somewhere—your parents’, a friend’s, or for a fee at a storage facility (enroll in automatic payments for it if that’s what you choose because your stuff will be out of sight out of mind, trust me); or you can sell what you don’t want to take with you—the most lucrative option of the bunch. You can throw out a lot, too, which will minimize the amount you need to take and/or store, and it takes less time than trying to sell it. What you do with your stuff depends on what you have and what you think you’re going to need wherever you’re going. When you’re in doubt about whether to take something or leave it, do some investigating and find out the cost to ship it—if it is more than the item(s) are worth, you have your answer! As for electronics, you may need a new sim card for your cellphone and/or outlet adapters for your plugs. If that sounds like a hassle, then don’t bother. Honestly, there are stores where you are going. They will have what you need.
As far as finances go, you will need to notify your creditors of your new address. It will also help to check with your bank. It may have affiliate branches where you are going, or it might be better–thanks to exchange rates and fees–to just open a bank account in your host country. You’re also going to want to find out if you are required to pay taxes on your income both at home as well as wherever you are living. It can get really complicated so talk to an accountant before you leave so that you aren’t accidentally breaking the law or saddled with fines.
Finding somewhere to live can also be a challenge. I came here with a job already in hand which made it easier for me to find a place to live. If you aren’t sure what you’ll be making and therefore don’t know what you can afford in rent, look around online to give you ideas of what the costs will be before you leave. Also get reference letters before you go so that you can give them to any potential landlords.
It may seem overwhelming at first but if you stay organized and create a to-do list, you will get through it all. It is definitely worth all the work!