Why a list of mistakes is not enough
Lists of trading mistakes are everywhere, and most readers nod along to all of them. That does not help, because you cannot fix ten things at once and you probably do not make all ten. What helps is a test for each mistake that you run on your own trades. The result tells you which one is costing money, and roughly how much.
Each section below gives the mistake, the journal test, and what a fail looks like. You need open and close times, prices, size, P&L, a planned stop and a setup tag for each trade. The trading journal spreadsheet has those columns.
Ten mistakes and the test for each
| Mistake | Journal test | Fails when |
|---|---|---|
| 1. Risking too much per trade | Risk per trade as % of account | Above your plan, or varies widely |
| 2. No stop before entry | Share of trades with a planned stop logged | Below 100% |
| 3. Moving or ignoring the stop | Losses in R | Losses beyond −1R are common |
| 4. Cutting winners short | Average win in R vs planned target | Wins well short of target |
| 5. Keeping a losing setup | Profit factor per setup | A setup below 1.0 over enough trades |
| 6. Overtrading | Results by trade number in the day | Trades past your limit lose money |
| 7. Revenge trading | Trades soon after a loss, size above median | Flagged trades lose money |
| 8. Judging by win rate alone | Expectancy and profit factor | High win rate, negative expectancy |
| 9. Ignoring costs | Fees and commissions vs net P&L | Costs take a large share of gross profit |
| 10. Not reviewing | Date of last review | More than a week ago |
Mistakes 6 and 7 have their own guides: overtrading and revenge trading.
Worked example: the setup that funds nothing
Mistake 5 can be among the most expensive and the least visible, because the total looks acceptable. A trader logs 100 trades across three setups:
| Setup | Trades | Win rate | Gross wins | Gross losses | Net | Profit factor |
|---|---|---|---|---|---|---|
| A | 40 | 55% | $3,100 | −$1,500 | +$1,600 | 2.07 |
| B | 35 | 54.3% | $2,200 | −$1,300 | +$900 | 1.69 |
| C | 25 | 36% | $900 | −$2,700 | −$1,800 | 0.33 |
| All | 100 | 50% | $6,200 | −$5,500 | +$700 | 1.13 |
The account total of +$700 and a profit factor of 1.13 look like a thin but working strategy. Split by setup, setups A and B together made +$2,500 with a profit factor of 5,300 ÷ 2,800 = 1.89, and setup C gave back $1,800 of it.
Twenty-five trades is a modest sample, so the honest conclusion is "setup C needs a closer look", not "setup C never works". Paper-trade it, reduce its size, or collect more trades before deciding. The point is that the total alone would never have raised the question. Check any row with the profit factor calculator, and see profit factor for how to read it.
Two quick tests for risk mistakes
Risk per trade. For each trade, compute |entry − stop| × shares ÷ account. If your plan says 1% and your trades range from 0.4% to 3%, results depend more on which trades happened to be large than on your setups. Use the position size calculator before each entry: position size = (account × risk %) ÷ |entry − stop|, rounded down.
Losses in R. Divide each loss by the planned risk. For example, entry $50.00, stop $49.00, exit $48.20: R = (48.20 − 50.00) ÷ (50.00 − 49.00) = −1.8R. A loss of −1.8R on a stop that should have capped it at −1R means the stop was moved, ignored, or gapped through. Gaps happen; a pattern of them on liquid stocks during regular hours usually points to the stop being moved. The R-multiple calculator does the arithmetic, and stop loss vs stop limit explains gap risk.
A monthly mistake audit
- Pull the last month of closed trades, or at least the last 50.
- Run the ten tests in the table. Mark each pass or fail.
- For each fail, estimate the cost: the net P&L of the trades involved, or the difference between actual and planned losses.
- Pick the single most expensive mistake. Write one rule for it.
- Next month, check the rule first.
Keep the audit sheet from month to month. A mistake that fails three months running is a habit, and it deserves a firmer rule, such as a hard size cap set at the broker or a bracket order on every entry. Fixing one mistake at a time keeps the change measurable. It also keeps the work small enough that you will actually do it. If you change five things at once and results move, you will not know which change did it.
A journal app that imports fills from your broker, such as TradeGreen, computes win rate, profit factor, R and expectancy per setup automatically, so the audit becomes reading results rather than typing them.
Mistakes this guide does not cover
Some mistakes cannot be found in a trade log: trading money you cannot afford to lose, using leverage you do not understand, or trading without a written plan at all. For the last one, start with a trading plan template; every test above compares your trades with a plan, and without one there is nothing to compare against.
If you have run the tests and still cannot find the leak, look at time of day and holding period, as described in why you might be losing money day trading. And for behaviour patterns such as hold time differences, see trading psychology through your own data.