Toast off cumin and coriander seeds then grind them up (or use already ground stuff if you want)
Soften chopped onions, add chopped garlic and chopped ginger (or use the premade pastes which are fine and can be frozen quite handily in ice cube trays in ready made portions)
At that stage add your spices, you’ll need to experiment a bit with what you like but I tend to like a teaspoon of turmeric, 3 teaspoons of cumin and 2 teaspoons of coriander, add chilli powder/cayenne/paprika or whatever to your taste at this stage as well.
Add in a bit of tomato puree and mix it all up into a paste.
At this stage add the thing you want to make the curry out of (chicken, chickpeas, aubergine, cauliflower, potatoes or whatever) and give it the requisite amount of cooking
Add a tin or two of chopped tomatoes and then top it up with water or stock, stir it and then let it simmer away for a while to let it thicken, sometimes if it’s a bit too watery I like to chuck some lentils in to add a bit more bulk and thicken it a bit as they absorb the excess liquid.
Keep tasting it to see if it needs owt, often whack a bit of lemon juice in at the end if I’ve overdone it on the cumin
Add a bit of garam masala at the end, mix in some chopped fresh coriander if you like it.
Eat it with rice or whatever.
Good thing about it is you can just dick about finding out what you like and what you don’t. The basic technique doesn’t change but it’s fun nailing down what you like.