Hello... This is janu How can i increase my marks from 300to 590..if I start preparing from now still only 30days left for Neet...?

If you have not studied anything and starting from the very first, it is impractical to complete the entire syllabus (97 chapters). If you have studied the theory portion, make sure you do these things to boost your marks and confidence -

1. Solving previous year question papers (min. 2012-2018)
2. Solving NEET Mock Papers

Read Bio NCERT thoroughly and solve exemplar questions of Bio as Biology is a subject where you can easily secure good marks. If you read NCERT line by line thoroghly, solve Bio exemplar book and prev year NEET questions of Bio (2012-2018), you can easily get 320+ out of 360.

To get 140+ in Chemistry , study these -
1. Atomic structure
2. Periodic Table
3. Chemical Bonding
4. Hydrogen
5. s-Block
6. Boron and carbon family
7. periodic properties and  oxoacids structures given in Nitrogen family, oxygen family, halogen, inert gas
8. General Organic Chem
9. Hydrocarbons
10. Haloalkanes, haloarenes
11. Alcohol, phenol, ether
12. physical properties given in ketone, carboxylic, ester
13. amines
14. equilibrium
15. electrochem
16. thermodynamics
17. chemical kinetics
18. polymers
19. biomolecule
20. chem in everyday life

Solve 2012-2018 NEET/AIPMT Chem questions

For Physics, recap all formulae and solve previous year questions and you will surely get 100+

So, 320+140+100 = 560

To enhance your rank, you may use NEET Rank booster provided by Careers 360 - https://www.entrance360.com/neet-rank-booster/ (tap on that link)

Be positive. Best of luck.