Positive market conditions mean there is a tendency Bitcoin Prices continue to rise throughout the day. For example this morning the price is 3.7 million, a few hours later 3.800.000 next 4.100.000 and so on. In this condition Bitcoin trade tends to be easy. Why ? because you simply buy at a cheap price and sell it at a price slightly higher than the purchase price.just enjoy the profit until the market rise is finally saturated then you should stop buying and wait for the price to fall back.
For buying, I would say you should buy whenever the price is down to a low point, cause you can buy at a high price and wont gain anything at last. When it comes to selling, there are no rules you make the rules yourself sell whenever you believe is the right time.