Here is a basic recipe to keep in your memory bank.

Remember, if you're going to put a sauce on a really good cut of meat, or if you're going to make a memorable meal, DON'T use leftover, non-descript wine in this sauce. It provides a basic flavor, so the better the wine, the better the sauce. It seems like a waste of a good bottle, and we, admittedly, have a lot of good wine to make this with, but you will do yourself a disservice to go cheap here.  Depth of flavor is good for cooking as for wine. Start all layers of flavor with a basic mirepoix:

2 carrots                   
2 stalks celery               
1 small brown onion               
2T olive oil                   
2 cloves garlic, peeled and minced
1 bottle red wine: Cabernet for beef or portobellos, or Zinfandel for pork
1/2 to 1 tsp thyme
salt and pepper

Cut off ends of carrots, peel. Cut into matchsticks. Pull strings from celery stalks, chop. Peel onion and chop
Put 2 Tablespoons olive oil in a skillet. Over medium heat, stirring occasionally, cook carrots, celery and onion until start to brown, about 10 minutes.

Add garlic, cook a couple minutes to remove the 'raw' taste. Add wine of your choice.  Reduce to a simmer, let reduce about 1 hour.

Strain out veggies, add thyme. Return to simmer.

Look to end up with 1 cup of sauce. Add salt and fresh ground pepper.