ginger isn't required for curry.
main thing for curry is a shitload of onions. depending on the kind of curry you can chop them and fry them, but tbh blending them is a safer bet.
also shallots or the indian shallots are slightly preferable to brown onions.
you will also want garlic and fresh chili.
powders of any kind are a bit of a no-no tbh.
as far as fat goes, yes you probably want a lot of it, either through fatty meat, or I think in Asian cooking a lot of oil or ghee, or through coconut milk. If you buy coconut milk in a can look for the one with the highest fat content (15g or so). Light coconut milk is idiotic.
Spice wise, fresh turmeric is fairly widely available now and much nicer than powder. It also keeps a long time. No need to peel just bung it in the blender with the onions, garlic & chili and any amount of water till it blends.
You're going to want to use various dry spices but for me coriander is always the key, it goes with anything. Cumin is for your dark meats like beef or lamb, with chicken you can consider fennel. I'd be looking at coriander being the biggest quantity say 1 tbsp, and the other ones maybe 1 tsp. Grind the dry seeds up first, so they're a powder. Add black peppercorns if you want things to be spicier, but it's a different heat from chillis and it's not required.
When you're cooking you can add lots of different whole spices, specifically some or all of cloves, cardamom pods, cinnamon stick, star anise (probably best with stronger meats). Give them a fry.
Curry leaves are good, but quite expensive and don't keep well in the fridge.
If you start off with some oil, frying the curry leaves, various dried spices will bring out some flavour, then add the spice paste (which is basically onions + chilis + turmeric, maybe ginger) and fry that before adding the meat.
You can add a bit of water if you've something that needs cooking for a long time like mutton, and then add in coconut milk towards the end.
Tamarind block (it's basically mushed up tamarind with seeds still in) can be used for fish curries and anything where you want a bit of sourness. Lime/lemon juice will do the same job before serving.
A more Thai style curry will use lime leaves (buy them frozen) & lemongrass (you can bash and add whole, or blend very thoroughly) to give a different flavour profile from Indian.
Sugar can help sometimes, palm sugar is better but not necessary.
Powders of any kind are a no-no.
You won't really go wrong if you have plenty of whole spices, lots of onions, fresh chilis, and don't be scared of fat.