How to select mark scoring questions in jee and not get negative marking

Remember these points for JEE Main:
Try to categorize the questions into various categories while attempting them during test series or while solving them at home. Almost any paper has three types of questions easy,medium and difficult. 30% of the paper will fall into easy,50% into medium and rest 20% into difficult.
Easy : Questions that can be solved within 30 secs to 1.5 mins
Medium: Questions that can be solved within 1.5 mins to 3 mins.
Difficult : Lengthy questions come here.
Now solve the questions in the order Easy,Medium and then Difficult.
Also, during solving the paper there should be rounds.
Round 1 for easy and medium and skip the questions that are taking more than 3 mins and some difficult ones.
Round 2 for those which you skipped during first round and almost solved them but due to some mistake you didn't get the answer but you know how to proceed.
Round 3 should be those questions which you think you might get an answer.