One of the main indicators of the market transactions is the Volume of transactions.
The Volume of finished transactions is characterized by an active involvement of participants in the market, its strength and intensity. Volume increases together with a steady uptrend when the price rises, and, hereby, decreases when the price falls.
http://www.ifcmarkets.com/en/ntx-indicators/volume-indicators
1. Accumulation/Distribution Indicator - http://www.ifcmarkets.com/en/ntx-indicators/accumulation-distribution
2. Money Flow Index (MFI) Indicator - http://www.ifcmarkets.com/en/ntx-indicators/money-flow-index
3. On-Balance Volume (OBV) Indicator - http://www.ifcmarkets.com/en/ntx-indicators/on-balance-volumes
4. Forex Volume Indicator - http://www.ifcmarkets.com/en/ntx-indicators/volumes