How you decide to use charts, I think, will depend upon what you want to get from them.
As far as trading is concerned the most useful piece of information is where the 'weight' of money is [IMO]. If a stock is going to rise in price it will do so because 'somebody' is spending their money. The volume and share-price movement will reveal that to some degree.
However, take a look at this chart posted by 'Bonehead1000' which shows how a big buyer will both buy and sell when they are accumulating ... so it is not always easy to 'read' the actions of others
Charting has a long history and some of it is really quite irrational. The psychology is a little suspect. Basically people are trying to 'master' an intrinsically uncertain situation and so, in my opinion, an element of superstition has insinuated itself into the 'art and science' of charting.
A chart can not tell you, in advance, whether someone with a large holding is going to wake up one morning and decide to sell. Nor will a chart tell you that they might change their mind next week.
That said, I do use charts to help me to decide when I might trade in or out of a position. But, for me it is only one piece of information among many. [A king has many advisers, but in the end, it is he who makes the decision]
