Updated October 2026. Part of the HalfTrend series. This article is about the principles that come before any live trade, whichever strategy you use.
A good strategy is not enough on its own.
Before it gets real money, it’s worth stepping back to the principles that decide how you build, judge and run it.
Trading and investing are different games
Trading isn’t a shorter version of investing. It’s a different discipline.
| Trading | Investing |
|---|---|
| Short to medium term | Long-term holding |
| Based on timing and patterns | Based on valuation and growth |
| Focused on price movement | Focused on business fundamentals |
| Frequent decisions | Patient conviction |
Investors compound returns over years. Traders try to capture a small, repeatable edge over hundreds or thousands of trades.
Why most traders lose
Most retail traders lose money. The reasons are rarely mysterious:
- They chase indicators or YouTube strategies they don’t understand.
- They override their own rules when it feels right.
- They treat trading as a game or a gamble, not a business.
- They expect to double their money in days.
- They don’t respect risk: they let losers run and cut winners short.
Trading is a probability business
The single most useful idea in trading:
Trading is a long-term, probabilistic business.
No single trade matters. What matters is applying a method consistently over a large number of trades, with a small edge, while making sure no single loss can do serious damage.
You only need a small edge
You don’t need to be right 80% of the time.
A strategy with:
- a 45% win rate,
- winners averaging 1.8 times the size of losers, and
- sensible position sizing
has a positive expectancy.
But the edge is the small part. Most of the result comes from:
- discipline,
- risk management,
- money management, and
- consistency.
The principles I follow
I treat trading as a game of probabilities, run by rules rather than opinions:
- Every trade is one in a large sample.
- Rules are set in advance and followed without exception.
- Performance is judged over months, not days.
- Losses are part of the process.
- A method should be repeatable by someone else.
Risk and money management
A great edge without risk control is a blow-up waiting to happen.
- Limit position size relative to account equity.
- Set a maximum daily loss.
- Avoid over-leverage.
- Exit by rule, not by feeling.
- Protect capital first.
Money management decides how fast you can grow without becoming overexposed to one market or one signal.
Why I write my rules as code
I write every strategy as code, even when I place the trades myself.
Code forces precision. If a rule can’t be written down exactly, it’s too vague to follow under pressure.
It also brings:
- no emotional reinterpretation of the rules,
- perfect repetition in backtests,
- protection against revenge trading and overtrading,
- risk and money management built in, and
- a focus on process, not on any single outcome.
Systematic doesn’t mean hands-off. A strategy still needs to be reviewed regularly, and you still need the discipline not to interfere with it on a whim.
Before you go live
Remind yourself:
- trading is not a get-rich-quick scheme,
- it’s a repeatable business of applying an edge, and
- results come from process, structure and patience.
And test the strategy properly first. Part 3 covers the robustness tests I use, and my book Seven Tests Before You Go Live goes through them in depth.