Yes for some leagues and no for others
You join a sport by either signing up at school or asking an adult
It depends on which sport you want to join, but generally, you just show up at an activity and tell them you want to join.
to join a clan in gunz you just have to ask a member or player with a clan and ask them to join. Some clans require pros so you might have to tryout in order to get into the clan.. :D
you had to work for it no matter what but you just had to work for it everyday and also IMPROVE your skill to join every years
By being drafted, attending an NBA team tryout, or being signed as a Free Agent.
invent a new sport!! or join a club
you can't encourage someone to join sport because it is a matter of there own free Will. therefore its not your choice. however people can want to join sport by seeing professionals playing the sport or doing a crazy stunt and the viewer will decide that he wants to join it because of his hero.
Go to a teams home website and find the contact number, You can then ask all the requirements and open tryout dates
to have fun :)