Pritesh, its very common among college students to get anxious about their placements in campus for big MNCs. But, believe me it the percentage of marks in 10th and 12th has very little weightage as compared to your overall performance in the various tests that you have to clear in order to get selected in placement interviews.
First of all your percentage of 60% in engineering is just fine. Every company has a different criteria of selection. Some companies are contend with above 50% in engineering with no blockages. Some want your percentage to be more than 60% with all blockages cleared, if any.
The companies usually test their candidates on the following areas:-
Once you clear the written tests, the companies want you to appear good in their group discussions which is usually followed with technical interviews.
At the end HR interview seals your fate. The HR interview is also very important since it tests your team working ability, personality and oration skills which have now become an important part of the desired candidates.
So I suggest you to be high in moral, good at your skills and confident during interview.