1. The best time to buy is when a stock is going down on low volume without influx of any news as compared to recent increases on higher volume.

2. This suggests that the selling is lighter and holders of stock are going to sell have finished and the rest are holding.

3. The sellers of stock then may come back into the market when they see the price stabilise.

4. Corollary to above statement is that sell on high volume on way up,as this usually creates abnormally high prices that cannot be maintained for long.