A lot of people like to tell you there are a whole let of very specific rules for how you should make, serve and drink tea, and they are all idiots. Tea is not difficult. It's not complicated.
Fortnum and Mason believe that water that has been boiled twice will taste significantly different to water that has only been boiled once. They don't seem to regard the different composition of tapwater from place to place as significant at all though, suggesting that they are, in fact, full of shit.
They also push the ridiculous n+1 spoons rule (one spoon of tealeaves for each person, plus one for the pot), which would only make sense if everyone used the same standard-sized pots and cups, because there's no way that three spoons can make the same tea if it's enough for two large mugs as it would if it were for two small teacups. The tea:water ratio is completely different.
The Royal Society of Chemistry maintains that putting the milk in first is essential. The Institute of Physics says they're wrong. The actual reason people started putting milk in first was to prevent poorly-made cups from breaking when near-boiling water was poured into them, and it was looked down upon to do that because it showed you couldn't afford the good china. But fuck that, it's just easier to pour milk in second because you can more easily see how much you're putting in. George Orwell was right about that.
He was wrong about the type of milk though, suggesting that skim is best. Maybe it's just that he didn't have access to homogenised milk, so perhaps skim was the better option at the time, but if you buy 2% or no-fat milk now then you are an idiot. Full-cream homogenised milk contains between 3.2% and 3.8% fat depending on brand, and if you think cutting that out is making a measurable difference in your life then you're right, but it's not keeping you healthier it's just making your milk taste terrible.
Douglas Adams made the bizarre suggestion of using teabags with a teapot, clearly not understanding the purpose of the teabag. If you're going to make it in a pot, use loose tea. If you're going to use teabags, just make it in the cup. The advantage of teabags is that you don't need the pot. That's why they exist.
I use both at different times. When making tea for myself alone, I use teabags. When making it for more than one person, I use a pot. It's just a matter of convenience, it's not important.
Of course, if you're doing a serious comparison then there is a set of universal and unambiguous rules you can use to make sure you make each kind of tea you're testing the same way: ISO 3103. I'm sure it has its value to tea-makers, but for the average person it's completely unnecessary, so here's a simple set of universal instructions for making tea:
You put tea leaves in hot water and then wait a while, then you can add other stuff if you like. Putting sugar in it is pretty disgusting, but if you like things that are terrible then go for it. Put it in a mug or a teacup or even a tumbler if you like, it's just a drink. The purpose of the vessel is to hold it so you can drink it. The shape of the thing you put it in doesn't change the flavour because that's impossible. It doesn't work for wine and it doesn't work for tea either. Just make a drink and drink it, do what you want.
My favourite way to make tea is to put one spoon of Assam, one spoon of Earl Grey and one spoon of English Breakfast into a pot big enough to make enough tea for two decent-sized mugs, steep it for a good ten minutes and add enough milk to make it cool enough to drink (in winter). In the summer I put the same amount of milk but also add a couple of ice-blocks to bring it down to a drinkable temperature.
And if you make it any other way then you are a filthy deviant who shouldn't even be allowed to drink tea.