Support and resistance is the most widely taught concept in technical analysis, present in every introductory trading course and referenced in most market commentary. It is also among the most inconsistently applied, largely because the standard explanation ("price bounces from support and resistance levels") leaves out the mechanics, the exceptions, and the rules required to turn it into something testable.
What support and resistance actually represent
A support level is a price area where, in the past, buyers have repeatedly shown up with enough force to stop or reverse a declining move. A resistance level is where sellers have repeatedly done the same to rising price. These are not magic lines drawn by technical analysis software. They are price areas where a sufficient number of participants previously made decisions to buy or sell, and where those decisions were validated by subsequent price movement. When price returns to those areas, there is reason to expect similar decision-making, though not a guarantee of it.
How to identify significant levels
The most common approach to identifying meaningful support and resistance levels involves three criteria: multiple prior tests (a level tested two or more times from the same direction carries more significance than one that was only touched once), prior swing highs and lows (the highest and lowest points within a visible range on the chart represent where price previously reversed), and round numbers (psychologically significant prices like 1.1000, 1.2000, or 2000 on gold often attract clusters of orders that create technical significance beyond the chart pattern alone). Not every level identified by these criteria will prove significant; the point is to identify the levels worth monitoring before applying additional confirmation.
Zones vs exact lines
A common beginner mistake is drawing support and resistance as single-pixel-thin lines and expecting price to react at the exact price of a prior high or low. In practice, price rarely revisits the exact tick of a prior reaction point. Zones (price areas of 5 to 20 pips wide on forex depending on the timeframe) are more accurate representations of where reaction is possible than single lines. A zone captures the range within which a prior reaction occurred, acknowledging that "near the prior high" is more realistic than "at exactly 1.08721."
Trading bounces vs breaks
The same support or resistance level can be traded in two completely opposite ways. A bounce trade enters in the direction of a reaction off the level, betting that the level will hold and price will reverse. A breakout trade enters in the direction of a level being broken, betting on continuation. These are not compatible approaches to the same level at the same time. You need to have a pre-defined view of whether you are a bounce trader or a breakout trader at any given level, based on contextual factors like the strength of the approaching move, the timeframe trend, and the number of prior tests the level has already absorbed.
Confirmation: rejection candles and reaction
Most experienced support/resistance traders do not enter on price touching a level. They wait for confirmation that the level is actually reacting. Common confirmation signals include rejection wicks (long candle wicks that show price was pushed back from the level intrabar), full rejection candles (an entire candle that closes back inside the prior range after touching the level), and momentum shift (rapid buying or selling that follows contact with the level, suggesting active participation). Confirmation reduces entries at false breaks but costs some entry price; the tradeoff between precision and price is a personal strategy decision.
Common mistakes
The three most common errors in applying support and resistance: marking too many levels until the chart is covered in lines at almost every swing, making nearly any price outcome appear "supported" or "resisted" in retrospect; ignoring higher-timeframe context (a strong support level on the 15-minute chart that sits inside a bearish trend on the 4-hour is far less likely to hold than one aligned with higher-timeframe structure); and redrawing or reinterpreting levels after the fact to match outcomes rather than maintaining consistent pre-defined marking rules.
From levels to a testable strategy
A support/resistance strategy that exists only as "I look for price to bounce off levels I identify on the chart" cannot be backtested, cannot be evaluated for performance, and will drift in definition as your recent trades influence what you consider a valid level. A documented version specifies: which timeframe's levels are relevant, the minimum number of prior touches required, the confirmation candle pattern required before entry, the stop loss placement rule, and the minimum RR required to take the trade. With these rules written down, every trade can be evaluated against whether you followed your process, and whether that process produces results worth keeping.