Make a list of tasks to complete: You don't want to leave your current tasks unfinished when you move to a new position. Hence, make a list of all pending or unfinished tasks and set a meeting with your manager. Together decide on what you definitely need to get done before the move, what can wait for your successor, and what can be scratched off the list. This will help you to set the right priorities and avoid the stress of getting everything done.
Train your replacement: You don't want to leave your team in a lurch when you move to another department. Therefore, meet up with your replacement and take the time to explain him/her the day-to-day responsibilities of your current role in detail. Pass on all the necessary files, and personally ensure that you introduce him/her to the rest of the team and help break the ice. This will earn you brownie points with your current manager, your team, and your replacement, and will reassure the management that you are a responsible employee.
Make new friends without foregoing the old ones: An internal transfer is a great opportunity to expand your professional circle and make new friends at work. So, while you may be extremely comfortable with your old workmates, take time out to know your new team. Hang out with them and make new friends at work. This will ensure that you have people to go to if you have questions regarding your new responsibilities and that you have a good, friendly environment to work in. This will also enable your new team to know you and accept you into their fold easily.
Make the most of your learning window: When you take on a new role, you are always given some time to take things slow and learn the ropes, so to say. Make good of this time to get up to speed with your new responsibilities and not to finish pending tasks. Otherwise, once this window closes, you will still be struggling to get on top of things.
Understand your new role clearly: Knowing what needs to be done will help you accomplish it more easily. Therefore, read the job description of your new role carefully and in detail. Have an in-depth conversation with your new manager about what is expected out of you and the established processes that the team follows. Ask him what hurdles you can expect and if he has any suggestions on how to cross them. Also, have some chats with your new colleagues and quiz them subtly on the team culture and the normal workflow. All this information will go a long way in helping you prepare for your new responsibilities.
By focusing on the abovementioned five ways to transition into a new role, you will ensure that you move smoothly into your new role and increase the chances of your immediate success at it.