For me the masala never turns out like I want it to. I don't know how to say this but .. err..it doesn't look right. I mean the onions and tomatoes and oil aren't mixed well and the color is never right, its either too dark or too light. I can never figure out at what point I need to put in the spices or when I have to add water to bhoonify it.
And the thing Sara said about slicing the onions in different ways and how it effects the dish.. that is so very true!!!
also "bhooning" the masala for a good 5-10 minutes before you add the meat/veggies is a good tip. My bhabhi told me to do that, and she makes amazing food.
if i have to add yogurt to the dish, i would blend it with the tomatoes and then add it.
i add a pinch of powdered garam masala to all my salans at the end.
also when im nearing to the end of cooking the salan, i cut up some green chilli peppers and add them.
i find that the food tastes better when i use ghee, instead of vegetable/canola oil