Hello aspirant,

YES, you can score a decent and, in fact, good marks in JEE mains ( around 150+), if you have Completed your JEE mains Syllabus completely and throuroughly, and have revised all teh chapter well. YOU must be determined towards your JEE mains syllabus and must have to make a proper time table for the same. Solve the previous year Question paper and sample papers to make yourself familiar for the exam.

Further, you can follow the below JEE mains Preparation tips and strategy to get extra marks in JEE :

Prepare A Well-laid Plan

Draft a daily schedule.

Prioritize the topics that require more time and relevant to the subject.

Stick to the routine and pay special attention to problems.

Get Hold Of The Syllabus

Manage your time effectively

Understand Basic Concepts

Before delving into JEE preparations, know the JEE syllabus and understand the basic concepts present in the syllabus.

Evaluate your knowledge on basic concepts.

Make notes on required topics.

Choose The Right Study Material

Further, you can also practice these below reference books to ace your JE Emains exam preparation well ;

JEE Main Books Important for Mathematics

Trigonometry by S. L. Loney

Higher Algebra by Hall & Knight

Maths XI & XII by NCERT

Coordinate Geometry by S. L. Loney

Problems in Calculus of One Variable by I.A. Maron

JEE Main Books for Physics

Problems in General Physics by I.E. Irodov

Fundamentals of Physics by Halliday, Resnick & Walker

Concepts of Physics Vol I and II by H.C. Verma

Books for JEE Main Chemistry

Organic Chemistry by Paula Bruice Yurkanis

Organic Chemistry by Morrison & Boyd

Inorganic Chemistry by J.D. Lee

Numerical Chemistry by P. Bahadur

Further, For more information and complete details about the JEE mains tips and strategies and about the subject wise weightage in JEE mains, you can follow the belwo link :

https://engineering.careers360.com/articles/jee-main-preparation-tips

I hope that this will help.