Hey!There

You have enough time for JEE MAINS for April session exam.You can get about important chapters of three subjects from where questions being frequently asked..I can hint some important chapters from three subjects;

PHYSICS-NLM, FRICTION, ROTATIONAL DYNAMICS,SHM,WORK POWER& ENERGY, KINEMATICS, ELECTROSTATICS, ELECTRODYNAMICS and  MODERN PHYSICS.

MATHEMATICS: TRIGONOMETRY, COORDINATE GEOMETRY, DIFFERENTIAL EQUATIONS AND APPLICATION OF DERIVATIVES,INTEGRAL CALCULUS and VECTOR 3D..

CHEMISTRY: ATOMIC STRUCTURE,MOLE CONCEPT,THERMODYANICS,CHEMICAL EQUILIBRIUM, GASESOUS STATE, SOLUTION,CHEMICAL KINETICS, ELECTROCHEMISTRY, ORGANIC CHEMISTRY, D BLOCK AND CHEMICAL BONDING..

If you covers these chapters with full practice of numerical,then surely you can score marks around of 150-170..

Ask if any query..

GOOD LUCK!