Tips For Gravies:

Always use ghee or vanaspathi with or instead of oil, which gives a good flavour to the gravy. If oil alone is used, it does not get separated easily from the ground mixture, as ghee separates from it.
Fry the ground masala in reduced flame, so that it retains its colour and taste.
Little plain sugar or caramelised sugar added to the gravy makes it tasty.
When tomatoes are not in season, tomato ketchup or sauce can be successfully used in the gravies.
To retain colour in the gravy always use ripe red tomatoes. Discard green portions if any.
Good variety chillies and chilli powder also gives colour to the gravy. As far as pos sible try to use long variety red chillies. Dry it under sun for few days and powder coarsely at home. Always the coarse powder gives good taste in gravies and pickles.
While using ginger and garlic paste in curries, always use garlic at 60% ratio and ginger at 40% as ginger is very strong and may make your dish sharp and pungent.