Trendlines
From a trader's perspective, a trend is a predictable price response at levels of support or resistance that change over time. Trendlines mark these levels, with support acting as the "floor" and resistance as the "ceiling". When prices break through either of these levels, that signals a trend for that movement to continue. It's easy to draw perfect trendlines on historical charts - but harder to be right when the trend is still developing. Still trendlines help focus your attention on finding support and resistance levels, the first step to identifying a new trend. Start by drawing trendlines over longer timeframes (daily or weekly charts) and then carry them
forward into shorter timeframes (hourly or 4-hourly). That way you'll highlight the most important support and resistance levels first and not lose the major trend development by chasing a short-term, minor one.