I got 50% in +2 sciene,want to do my future in engineering and did n't appear Jee-main 2016. So please suggest me what do i do...??

I will recommend that you drop a year and prepare for engineering entrance exam so that you can do engineering from a good college. Dropping a year means that you will get sufficient amount of time to prepare for competitive exams. It will allow you take mock up tests and help to score good rankin