In 3 conditions
1,When the strong fundamental stock in spot light have at least 30% price correction from the historical high and the trade volume in green and price starting to move upward.
2,When the stock in historical low (weak fundamental stock) trade volume in green and price starting moving upward in slow pace (short term trading)
3,When the stock is keeping moving upward from a low price which in futuristic demanding industry.

Before buying a stock ,choose the stocks and saved it in the watch list with criteria which are
1.Medium ,High cap
2.Upward revenue and net profit compare to previous seasons,years.
2.Free of debt
3.stable dividend payout
4.Future relevant
5.Industrial leader
Buy in batch when the stock in bad news,the world economy crisis hit,wait while the price dipped till stop dipping then start going upward.
Buy in batch when the good news for the industries cheering up,price shoot up at the beginning stage toward historical high.
Sell in batch when the price hit historical high while the revenue ,profit or dividend reversely proportional  with the stock price hike.
Sell in batch when the bad news remain and the stock price keeping on climbing up.
Investment carries risk
Thank You,Good Luck.