There isn’t just one way to make a good cup of tea -
everyone has their own way and everyone is right.
The most important thing about making a pefect cup of tea is the temperature of the water. Too hot and it will scald the tea - not hot enough and it will not infuse properly. Then it is a case of leaving it for the right length of time so that the flavours permeate.
When making tea in a mug or cup, the perrenial question is whether to put milk in the vessel before adding the hot water of after. The simple answer is after. This allows the water to be the right temperature to infuse the tea.