My recipe
This is what I use. It has been as effective as the Tide I used to buy - and Consumer Reports just rated Tide very highly.
1 bar Dr. Bronner's soap (I use lavendar, but any scent is fine)
2 cups washing soda
2 gallons HOT water
Grate soap and place in pan on stove. Add just enough water to cover, and simmer over low heat until soap is melted.
Dissolve washing soda in hot water. Add melted soap and stir well. Let sit overnight. Use 1/3 cup per load.
I pre-treat stains with bar soap. (Dampen the spot, dampen the soap, rub the soap into the spot.

Use an old toothbrush to really rub the soap into the fabric on tougher stains.)
I don't use Borax at all. It is tough on fabrics, and, since it's a mined substance, it's hard on the planet and on the people who mine it.