From OPT to H1B


I am going to start my OPT in the end of this January. But I want to continue with my H1B in one year, but I know the applications opens from April 1 every year.

My question is: Should I start finding a sponsor already this April, or can I start for next year?

Has anyone been in a similar situation? And If I start next April, how can I get the gab cap?

Thank you!