What kind of monitor is it?
What is your operating system?
What do you use to calibrate it with?
What types of lights are in the room?
What colour are the walls in the room?
What colour space do you save your image as?
Do you up load with an ICC profile included?
Do you soft proof?

The questions are many but all are important to get the image off of your screen and onto another. BUT and it is a BIG BUT, if the other person isn’t doing and least half of what you are then it will never look the same. The best you can say is it left your screen looking the way it should and IF it is viewed in a colour managed / controlled environment then it will look the same!

Alistair