Give me some tips for cooking the best bolognese sauce.

In order to cook bolognese sauce, it is important to use quality ingredients. You're going to need the following: Italian tomato sauce, onion, celery, carrot, minced meat, extra virgin olive oil, salt, white or red wine and milk. Here are some useful tips:

- Take your time. Cooking a great bolognese sauce takes at least 4 hours. Set the stove level at low.
- Start by cooking the "sofritto". This is a mix of chopped onions, celery and carrots. -
- Add the meat to the "sofritto". Be sure to seal it so it doesn't leak water into your sauce. 
- Add some wine and boil it completely.
- When there is no liquid left, add the tomato sauce and some water, and cook it for at 3 to 5 hours. You can add more water during the process if needed.