The devil's in the details. Write what you know. These are common mantras for aspiring writers. One way to utilize them is to try new things. Like going for high tea and photographing your meal so that you can remember the little things that most people would miss. Remember your impressions, remember the tastes and sounds.
For example, my husband and I ordered different teas on our outing. Mine was darker and more coppery coloured than his, a situation that got worse for the second cup as the tea was more concentrated and bitter. So I added cream. And extra sugar. The finger sandwiches were a tiny bit dry, but the combinations unique and delicious (smoked salmon, cucumber and dill cream cheese; baked apple, aged cheddar and branston pickle). And if you've never had true clotted cream, it's much thicker than you'd expect. I thought it would be like whipping cream while it was closer to a whipped butter consistency. It was also less sweet than I'd anticipated, making the addition of jam on top almost a necessity (if you have a sweet tooth like me).The three tiered tray didn't look like it held enough food to satisfy two people, but if one alternates with the tea and spends an hour or so over the food, it does its job nicely.
There's a lot of detail that can be added to a scene. Part of the trouble is deciding how much is enough without boring the reader. Another problem is trying to pick out details that make your telling unique. If everyone mentions adding cream and sugar to tea, perhaps mentioning the interesting pattern of shadows on the cup would be better, or the bitterness of the tea before the sugar is added.
Rituals are great for explaining how places work. A scene like high tea could show the aristocracy reveling in excess (both due to the specialized nature of the food as well as the end cost of the meal). It could also be used as a celebration for someone in a lower class who has saved money for this event. How they are treated and how they experience the event (do they eat slowly, use the correct cutlery, look around feeling embarrassed or do they ignore everyone else and focus singlemindedly on the meal) can tell a lot about the characters as well as the society they inhabit.
And you don't have to do everything yourself to learn the details. The internet is rife with pictures, reviews and descriptions of almost everything you'd like to know. When writing, details, especially as they relate to the senses, give life to a scene.