Waiting 5 to 10 Minutes
Rule: Wait until at least 9:36 preferably 9:40 to start trading.
Waiting 5 to 10 minutes is one of my most important rules in trading the open. The entire reason the profession is called "Pattern Day Trading" is the need for patterns to form, the pattern is my edge . Therefore I must wait on a pattern to form before any trade. At a minimum 5 minutes can form a pattern, but I find it better to wait at closer to 10 minutes for intermediate traders and longer for beginners.
The longer I wait the more decisive the patterns that form, up to a point. Also the longer I wait the calmer and more predictable the stock will become, up to a point.
I find that on the average day after about 11 AM and certainly after 11:30 AM the Stock Market in general starts to become difficult for me as a day trader, at least for my system. Strange things happen during the lunch hours and beyond. I believe mostly due to the low volume compared the first 1 to 2 hours of trading.