While away for a recent holiday my reading material consisted of two classics by Mark Douglas - The Disciplined Trader and Trading in the Zone. For many Trading in the Zone this isthebook that brought trading psychology to the masses.
"Accept, then act. Whatever the present moment contains, accept as if you had chosen it. Always work with it, not against it." - Eckhart Tolle
Every moment in the market is unique. Price can move in either direction in the next few seconds, the next few hours, the next few days, weeks or months. Despite what some people may say, you don't know what will happen. Price may be trending one direction on one particular timeframe, and could be trending in the opposite direction on a different timeframe.
How you interpret what price is doing, and how reactive you are to any changes in price behaviour, will depend initially on those core beliefs you have about trading, and from there your own rules derived from those beliefs.