Charu, 

If you prefer coll above branch then you should fill all best colleges at top positions like

NIT TRICHY CS

NIT TRICHY ECE

NIT TRICH EEE

NIT TRICHY MECHANICAL 

NIT TRICHY MME

..........

NIT SURATHKAL(write all branches) 

NIT WARANGAL(all branches) 

This may seem funny that to get these NITs at 40K is impossible but if some of the top rankers do some mistake in choice filling then you may get it. 

So repeat the same process write the best colleges (along with their branches)  . In simple words fill the choices in decreasing order.  Fill the best colleges first and the colleges you can get based upon previous year closing ranks put them at last after the colleges you want to take admission in. 

Hope it helps