when you try your strategy in a real account , try to make sure a minimum 35% return from that , otherwise, it just wasting of time. so develop your strategy time to time.
traders should choose the pair which is more appropriate to the concept of trading that will be used, if love scalping should choose the pair which has most lowest trading spreads.
generally, traders take demo account for practicing but this level does not work actually , for practice in a proper way i think live account best even though it is a little bit expensive.