It is always a good idea to scalp in the direction of the main trend. For example, if the trend is up on the higher timeframe of H1, you can enter into a long trade whenever there is a moving average crossover on the lower timeframe of M5 in the direction of the main trend on H1. You can read this whole short term momentum forex scalping strategy nicely explained on this dailyfx article. You can also use this short term momentum forex scalping strategy for trading binary options. This is how this scalping strategy works. Use the 2EMAs like 21EMA and 50EMA to determine the main trend on H1. If the trend is up, enter long whenever price bounces up from 21EMA on 5 minute chart. Read the above article, it explains everything in detail.