A trend line turns the swing points from the last lesson into a single, visual guide rail. In an uptrend you connect the higher lows; in a downtrend you connect the lower highs. Done well, the line shows the angle of control and gives you a moving level to react to.
Drawing a valid line
- Two points define a line, but it takes a third touch to confirm it is real.
- Connect lows in an uptrend, highs in a downtrend — the side the trend is leaning on.
- Prefer wicks-to-wicks or bodies-to-bodies consistently; do not cherry-pick.
- A steeper line is less sustainable — near-vertical trends almost always break.
Channels
Draw a parallel line on the opposite side of price and you have a channel. The trend line is the support rail, the parallel is the resistance rail (or vice versa in a downtrend). Channels give you both a place to enter (a bounce off the trend rail in the trend's direction) and a place to take profit (the opposite rail).
Breaks and retests
Trend lines matter most when they break. A clean close beyond the line signals the trend's angle is no longer holding — but the highest-quality signal is the retest: price breaks the line, comes back to it, and rejects from the other side (the polarity flip you saw with support and resistance). A break without a retest is more prone to being a fakeout.
Pitfalls
The biggest trap is forcing a line through price until it 'works' — that is drawing your bias, not the market. Let the swing points place the line. Also remember that on assets that move in large percentages, a log scale often shows a truer trend line than a linear one, because equal percentage moves get equal vertical space.