First, understand the role you have to play in your team. The goalkeeper wears the number 1 jersey; defenders wear numbers such as 2, 3, 4 and 5, 6, 7 and 8 are four numbers worn by the midfielders. 7 is an extremely important number because he/she is the playmaker of the team. Another important number is 10 and this player is considered to be the key person for the team. 9 and 11 are both used for strikers. While 11 is a more creative striker who can shoot the ball from anywhere, 9 is more like a poacher who is at the right place at the right time. Decide the role you want to play in your team and select from one of these 11 numbers.
There are other numbers which you can wear as well. You have a choice between 1 and 99 and you can select any number of your choice. However, all the numbers above 11 also have some significance. For instance, the number 12 is mostly used by the player who is considered to be a second priority striker. Number 13 is used by a second priority goalkeeper. Number 16 is used by holding midfielders. Similarly, 23 and 27 are used by creative midfielders. Therefore, be careful about the number you select. A defender wearing the number 7 will definitely not look good.
You can also opt to wear the same jersey number as the year or day you were born. The Brazilian legend, Ronaldinho, wore the number 80 because he was born in 1980.
Lastly, you can select the jersey number which your favourite player wears. For instance, if Cristiano Ronaldo is your favourite player and you think you play in his position as well, you can opt for the number 7 since he also wears the same.