how to cover syallabus of entire 1st year in just 7 months for JEE preperation

See if you have 7 months and you want to cover up the 11th syllabus then I would recommend you to keep the preparation simultaneously i.e., you will have to study for 11th and 12 th simultaneously. Now you have to find a correlation between these two year syllabus. For example, if you are studying electrostatics then you should study the 11th portion of mechanics as in Electrostat you will get some analogous problems to mechanics like charge sphere hanging through a rope or a spinning charged sphere etc. Now when you are studying mathematics Integration for 12 then you should study the 11th Differentiation, Limits etc as class 12 have Continuity and Differentiability etc. Like this you have to find simultaneous subjects which will help you studying.

Now for chemistry I would say Organic is really important and for physical chemistry if you are reading Thermodynamics for Physics then you can merge the same with the physics thermodynamics. So in a way you will save time. Inorganic can be tough but if you can you should try to complete the organic and inorganic as much as you can.

For JEE preparation tips visit the link below:

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

I hope this answer helps. All the very best for your future endeavors!