Maybe there is an opening sequence of tasks you do before the market opens. Perhaps in the middle of the day you draw swing charts or take periodic readings of the market's action. Maybe you keep a journal and make notes to yourself. Salesmen are taught to do small rituals before cold calling clients. It controls the anxieties and fears of rejection.
Baseball pitchers have a pre-wind up ritual.
It calms their minds and puts their body on the autopilot mode. One of the more common rituals on the trading floors was to wear the same disgusting lucky tie every day. This gets oxygen to the brain and keeps the blood flowing. Or perhaps you drank too much wine the night before or are jittery from drinking too much coffee. Sure, most of these are minor factors but they can all add up to major bumps in your performance.