Getting to be the best squad in Star Wars Galaxy of Heroes is no joke. Not only do you have to pick the best characters to start it off, you gotta choose your sides very carefully. First, you need to pick the light side or dark side.
Do you have a dark soul? Then taking your chance on an arena team as the dark side is the way to go because you can use awesome characters like Darth Vader and Darth Maul. Make sure to surround your Jedi with death troopers to soak up the damage and deal out fantastic special abilities only Dark Side has access to.
The light side is also a harmless fun filled with daze and data mine. Boba Fett? Check. Yoda? Check. Possibilities to form the killer team on the light side is very difficult without arena tokens. However, recruit Anakin and force him to be a healer. You can also get iPad version of the game to turn on the god mode which does require use of cheating tools.