Janna is my most played champion, what she lacks in damage she makes up in utility. Her wind gale, shield and ultimate are what makes her in my opinion one of the most powerful disengage champions in the game. She’s a great support if you have a strong tank front line. Whenever a strong front line lacks i prefer to choose a tankier support. Such as leona or shen to make up for the lack in front line. However if we lack a strong tank front line but we do have a strong engage team I often choose janna to make up for the lack in disengage. So it works both ways. Her spell kit, crowd control and movement speed is what makes her a very strong pick in either scenario. With over 5000 games played since season 1 this is by far my go to pick.
Early game items
Early game tactics
Early game tactics explanation comes here