There are no secrets, there are patterns plus a competent and thorough analysis.
Experience and daily work will lead you to good luck.
What is a skew and how to determine it? It is not hard. Pay attention to the performance of the match. For example, in the NBA, she just scales. This indicates that bookmakers, when setting quotes for total matches, underestimate them on TB, overestimating TM. This makes sense for the bookmaker, there is a reason: they understand that many will bet on TB, and since this option is often passable, it is not profitable for the bettor to win. Therefore, they reduce the odds for the probable total, and set the total above the average. Sometimes the bookmaker goes too far, and this skew in the line is clearly visible, which should be used by the bettor.