Welcome!! This thread has been heating up lately... If someone posts about a cancellation, you can PM them to try and coordinate - basically, you agree on a time, they drop the ressie and you keep refreshing your screen to hopefully grab it. We didn't book 180 days out so everything I have is a picked up cancellation, mostly just by chance. There's not better time of day really... if you are looking for one meal, one particular day then your best bet is to use the online site and just keep refreshing it during the day. If you are like me, and are flexible on your date / time then you can use the Dining Search tool
here. I've had a lot of success with this.