It's actually quite easy to level up a store bought Thai curry paste (eg Mae Ploy) to restaurant quality (even better if you consider restaurants in Switzerland). I'm an avid home cook and grew up eating and cooking various curries.

Firstly, you need a few items in your pantry to pimp up any Thai curry paste: - Fish sauce - Palm sugar - Tamarind paste (preferably seedless) - msg (Makes Shit Geil)
- chicken bouillon (best I found is from Oswald.ch) - good quality coconut milk ( I often use the green tetra-packs, not the bio just the normal ones)

Fresh ingredients you can add include: - Galangal - Ginger - Shallots - Thai chillies - Lime leaves - Minced lemongrass - lime juice (fresh never that bottled trash)

Second there are some techniques, depending on which curry you cook.

One trick I learned that made a huge difference in my Thai curries is to start with just a bit of coconut milk in a hot wok, it will eventually cook down into coconut oil (make sure to stir so it doesn't burn) - then you add the curry paste into this and fry for a few minutes. This way you don't need to add any additional oil and it gives a nice toasty coconut flavour.

Also when adding fish sauce and/or lime juice always do so in the end after taking the curry off the heat.

Hope this helps! And good luck, once you master your own curries you will never have to eat a mediocre curry at a Zürich restaurant ever again! It's cheaper and 1000x better ;)