There's no true strategy. Shows can change what tickets are available throughout the day. So, the ticket bought at 1:45p is better than the one if you queued up at 9 a.m. and waited for an hour to be one of the first at the window.
That said, TKTS often sells the highest priced tickets only, so 50% off may mean you are only getting $75 (regular $150 tickets), so TodayTix sometimes give you other options as far as where to sit at different price levels. Something to consider.
And I think the code SUBWAY gets you $20 off your first order, if you never used it before, before one of these hippies jumps in trying to sell you that $10 off is better because then they get $10 off their ticket, too, heh.