in order to our trading understanding we the traders generally choose our trading pair n, should choose the pair which is more appropriate to the concept of trading that will be used , if love doing scalping should choose the pair which has narrowest trading spreads.
The pair makes no difference, other than the time frame and trade size you need. For example, I can trade USD/MXN just as easily as USD/CAD. However, I based trades off of weekly charts.