Well, the setup was good but still the trade reversed quickly. So why?
From my analysis the ECB's interest rate decision was more dovish than expected cause the euro to strengthen via dollar selloff. This is currently happening across different currencies.
I size my trade by risking a certain percent of my account. I do not necessarily use all leverage available to me by my broker.
It goes like this:
Lets say my my account is worth $10,0000.
I want to risk 1% on every trade so that would be $100.
In this trade, the difference between my entry point & Stop Loss level is 15 pips (0.0015).
So I do 100 / 0.0015 = 66666
Since 1 lot is $100,000 we now divide: 66,666 / 100,000 = 0.66
This tells me I can trade a total of 0.66 lots.
I personally divide this up into 3 pieces (0.22 lots).
I set 2 take profit targets along the way at resistance/support lines + 1 piece that I leave and only advance the stop loss. This way if the trade moves in my direction for a long period of time I can "ride the wave".
Hope it was helpful.