hello sir what is the minimum percentage in +2 that should be achieve by a candidate for a good ranking in IIT JEE entrance exam??

dear nausheed 
12th board percentage will not matter in iit jee ( jee advanced ) ranking . 
only u need to score 75 percent in 12^th board , so, that u will be elligible for the exam . 
and the ranking on jee advanced are purely besis on merit list and your score on jee advanced paper . 
HOPE IT HELPS 
REGARDS 
kindly approve