The simplest way to establish a long/short bias is to draw a horizontal line on your chart.
Your bias is long above it and short below it.
This approach will keep you in line with the momentum.
The reason why you choose a particular place does not matter so much.
The most natural place however is the opening price of the instrument.
Mark the daily, weekly, monthly, quarterly and yearly open levels on your charts.
That way your bias is in sync with the direction of the candle.
The underlying principle is simple, its implication is profound.