First of all, 500+ won’t be able to do much even in 2018. So aim for at least 600+.
Secondly;
- You’ll need to put in at least 6 to 8 hours a day,
- Be very thorough with NCERT (specially for Biology),
- Step way outside NCERT as NEET isn’t a carbon copy of your text books,
- Practice Physics and Chemistry numericals,
- Keep in mind exceptions in Chemistry and Biology as they’re always targeted in NEET.