Never use curry powder, curry paste or curry sauce when making curry and never use someone else's recipe. Get down to your local Asian sweety shop and get yourself a bag of: garam masala, cumin, turmeric, chilli powder (hot), ginger and coriander. You'll also need butter, onions, garlic and tomatoes, a splash of good vinegar and some decent stock. Start with a tea spoonful of each spice fried up with the onions and garlic and see how it goes. Within a few sessions you'll hit the right combination - think of it as the culinary equivalent of messing around in boats.
Fresh chilis, ginger, curry leaves, bay leaves and coriander are also the way ahead, giving more depth and layers.
Use ghee, which isn't quite butter, it's clarified butter so withstands higher temperatures better.
Recipes are a good way to learn, there's always something to learn, unless you're a grade "A" thundercunt of course. I was recently introduced to this channel by one of the posters on the cooking thread. He's tops, look for his stuff on youtube.
None of which addresses @vvaannmmaann 's mum's curry because it isn't about curry, it's about shit loads more. Try carnation as I said, I know it's pants but it's that authentic 60's thing.