This book is pretty good. 83p for the kindle edition.
The method is pretty much the same on every curry. Fry an onion, remove from pan, blitz with a plum tomato or two. Fry your dried spice, then add meat, veg or whatever. Then return the onion tomato mix. Simmer on lowest heat for a while.
The balti and jalfrezi recipes are my fav from the book.