Ncert is the key .... Do all its intext illustration,inchapter problem and back exercises..
Plus read all theory points also... Like in many chapters like solid states , solutions u will find many imp theory points... Make note of them will be useful in boards + main
Then after completing chapter to get idea of current question scenario do the chapterwise ....
First grasp chapter like chemical bonding, periodic table and practice their question from previous year book. They will give us a general idea of imp properties and stuff like the general increase decrease in radius bond enthalpy etc.
U will find that u have to memorise 90%stuff but the rest can be easily be understood.
First make good quality notes in classes. They contain many imp illustration. For practice use MS chouhan jee main book.it is more than enough. Also do read ncert for getting additional memorisable theory which ur sir might miss.