[waveslider]

I think you're right about where to start, in general I've found that a good place to begin a trendline or pitchfork is at a place where momentum begins a new wave.
So not necessarily where price peaks/troughs, but where the actual momentum begins, if that makes sense. Placement should coincide with an area of low volatility, because that's a place where price has settled a bit and a new trend can initialize.

NIce chart you posted.