What plans should be made for cracking JEE exam 2018 in ONE year by a dropper?

Daily efforts_cover all 3 subjects daily_if not possible then just revise your coaching notes daily.
Revision of your notes on daily basis and some conceptual questions would help you to face test series...after you are done with this you can improve your score by minimizing your mistakes.
Stay motivated and competitive throughout the year _and most importantly don't ever think that u'll manage later_what's left cannot be revised later..so be regular from the first day.

In my case i took fiitjee for 1 year and didn't changed my strategy of managing in the end..i beleved that i could not make it and sarted chilling out with an average group of friends and a girl who keep asking me her doubts_and i was able to solve them all with my previous talent u may say_it also helped me to stay motivated but i was not able to make out the best from my side what i feel now_finally in the end i took little efforts to make my cbse boards percentage better and just started to focus only on easy chemistry and easy maths_as a result i finally got 42 in chemistry 40 in maths and 17 in physics {rank 75114} and qualified for advance 2017 going to be held on 21 may.
But what i feel now is that i can score its double if i enroll again and do what with i left this year.

Anyway best of luck bro!
Hope it helps.
Sawan Chaudhary