Heat the oil and fry only the onion till nice and brown.  Add garlic and brown some more, only takes a few minutes.

Add chilies, meat, ginger, seeds and cayenne. Stir around and cook till meat is no longer pink.  Add water and tomatoes, boil, cover, simmer half an hour.

Add vegetables, salt, garam masala, lemon juice and maybe some more water if it's looking dry, so that there is enough water to cook the vegetables. Cook till the vegetables are done, some take longer, this just takes practice.

To server, scoop the meat and vegetables out of the liquid, which is mostly fat and very gross indeed.  Use a slotted.  Serve with naan and/or rice.  This is really good and moderately hot.