Simple...last two 'highest' highs and last two 'lowest' lows. Resistance must be sloping down and support must be sloping up. Timeframe, bar chart, candle chart make no difference. Update everytime a new 'highest' high or 'lowest' low is formed.
As the second poster mentioned Taking the primary high and low, then the secondary high and low (The high and low in between the highest and lowest point). It now all depends on which time frame your interested in using. I for one use 1m tf, because 1m is the best strength indicator. When a primary high or low is broken, the candle which breaks it (closes across it ) will past it by more then 8 points by the time the candle closes. Take today as an example
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