The best predictor

The single best predictor of trading success is when the average P/L of winning trades exceeds the average P/L of  losers -Dr Brett

This figure readily available from trading software

I  want my Average Winner $ > Average Loser $..

then aimed for weekly +ve,
monthly
if I have 3 years consecutively positive MONTHLY AW$ > AL$ then I shall belong to professional level : a full time trader
Why monthly ? It is the best time frame for an income :)