Let's start, 5 minutes ago I opened two positions, one AUDUSD Long and one NZDUSD long. The starting trade size is approx 10% of my target position size, so I will add 9 more trades to this position. Because of low volumes it is best to start with a small trade to test the waters. If the market is affected by my trade I wait a while before I enter the next, say 15 minutes later. If I feel completely ignored by the market at trade entry then I add 2-4 increments of 10% until the price reacts to my entry. An easy rule of the thumb I often use is to enter next increment when the previous has turned green.
Last but not least; manage greed properly, in order words adhere to vast risk management and do not digress in any circumstance. Happy trading!