learning...good luck with the Renko system. Using a little judgement, based on where the days price has closed, relative to the reversal level......along with looking at a trusted friends comments, or a trusted indicator, can help to mitigate the inevitable whipsaws.
Whipsaws are the only thing which keep it from being the grail (almost)...and avoiding, or limiting them helps a lot.
And, patience is needed...if your luck is like mine..when you start following a system, there will be a shakeout. I try to tell myself that only the strong survive, and if I do the best I can, the market will trend once more, and the profits follow. Regards.