The first thing to do is to read the rule book for the governing body for your sport. You don’t want surprises. I read the rules two nights before my first competition and was surprised to find out rules that I did not know existed. You do not want surprises on competition day.
Prepare the same way you will compete. For example, in powerlifting there are commands for each lift. Practice your lifts with a training partner giving the commands.
Remember, it is not where you open but where you finish. I am guilty of this and learned it the hard way. I went into a competition with the thoughts that my openers would set records and win the Nationals. I went home empty handed. We saw the same thing in the recent Olympics – a lifter failed to complete the opener and was disqualified. Be smart – open safe and then have fun.