In practice
Overtrading comes in two forms: too many trades and too much size. Both usually grow out of boredom, impatience or the confidence that follows a winning streak, and both raise costs while lowering the quality of each decision.
Traders control it with fixed limits, such as a maximum number of trades a day, and by scoring each trade against a written checklist of what a valid setup looks like.
What to watch for
It often feels like hard work or commitment. A day without a trade is a normal result of following a plan, and costs are charged on every trade whether it had an edge or not.