You will need to see an abnormal amount of successive high volume days without the expected price movement up. The move up will be stronger the longer the sideways period takes place, and it doesn't have to be high volume for the entire duration of the sideways/channel trading, just the last few days before the pop.
But at the moment mate all that you're actually hoping is to see this sideways movement and a stop of the slippage. There are also other indicators of price manipulation by big players (you want this) because it means there is worthwhile money there ready to move the price up when their ready, but this is more subtle and I can't go into it all - you'd literally need to sit in front of your screen and watch the daily trades to pick these signals up.