When prices touch the upper Bollinger limit, this signifies there is an opportunity to consider concerning the sale of the investment. Conversely, when prices reach the lower limit, the standard practice is to consider taking a long position.
The Market Psychology of Bollinger Bands As these bands are so widely viewed in the marketplace, anyone considered trading activity should be aware of the significance when prices approach upper and lower band limits, as these are the most common entry and exit points for market participants.
More often than not, one can visually confirm on a historical price chart that prices tend to reverse themselves when activity reaches the levels as represented by Bollinger bands
RSI
The first technique is to use overbought and sold lines to generate buy-and-sell signals. In the RSI, the overbought line is typically set at 70 and when the RSI is above this level the security is considered to be overbought. The security is seen as oversold when the RSI is below 30. These values can be adjusted to either increase or decrease the amount of signals that are formed by the RSI.
Williams %R
Developed by Larry Williams, Williams %R is a momentum indicator that works much like the Stochastic Oscillator. It is especially popular for measuring overbought and oversold levels. The scale ranges from 0 to -100 with readings from 0 to -20 considered overbought, and readings from -80 to -100 considered oversold. 
