How tough is it to grab a top 50 rank in it jee? Roughly what type of preparation is required?Any special tips for how to have a deep understanding in physics?

there is not such things , dnt think the people who are getting this rank have some special type of brain , they are like us normal human being . 
but they utilised the brain in more effective way , thats the diffrence . 
u need to do the following work for getting such ranks . 

1- frst of all make a time table and stick to it but remember time table needs to be properly followed . 
2- measure your progress in each and everyday . 

3- take a test series . 
4- choose the right quality of material . 
5- compete with students from all india level and keep yopurself motivated 
6- per day atleast 6 hrs of prep on jee level . 
ALL THE BEST