It's just like any other skill, you just practise it. There was a time when I couldn't integrate some problems, and then there was a time where I could integrat

It's just like any other skill, you just practise it. There was a time when I couldn't integrate some problems, and then there was a time where I could integrate e^ax times sin (bx) automatically without even thinking about the process. I just practised by observing and now everyone thinks I'm good at interaction.