In calculus, which part should i give priority :-

1. Limits and continuity.

2. Differentiation.

3. Application of derivatives.

3. Indefinite integration.

4. Definite integration.

5. Application of integration.

6. Differential equation.

Please give answer in decreasing order of priority.

you should start from limits as it will be useful in continuity and in differentiability
there is no priority here they are connected
but most part come in IIT from definite integration then appliation of derivatives then limits and cont then differetial equation and then application of integartion