If you don't have a pressure cooker, please, go buy one. There's no reason to boil beans for hours on end waiting for them to soften.
You need to soak your beans. I like to soak mine for between 4 and 12 hours. In a pinch I've made them without soaking them but I think the results are sub par. Drain, rinse and put more water, about 2 inches deep past the top of the beans. Put it on high uncovered while you add the spices. Here's the list
1 lb. dried pintos
Put these in before you boil
1teaspoon - 1Tablespoon cumin
1teaspoon - 1Tablespoon coriander
1/2 - 1 teaspoon cayenne
2-3 Tablespoons molasses
Splash of Olive oil
A jalapeno or two cut into large pieces
Splash of Stubbs smoke flavoring
Put these in after boiling
~1/8 cup balsamic vinegar
Copious amounts of salt
Of course these are all approximations and can be altered to suit your tastes and the quantity of beans your making. I don't measure anything, but I am a good approximator.
After adding the top list, get your pot pressurized. I use a 15 lb. weighted gauge pressure cooker. Once it's pressurized I cook the beans for around 35 minutes. This gives me a nice tender bean. The elevation you live at will also make a difference in the cooking time. I live at 3200 ft. Keep in mind that the higher your elevation the lower the temperature at which water boils. In other words, if you live at the beach you may want to check them a little sooner.
Once the time has elapsed I put the pot in the sink and run cold water on the lid until it's depressurized inside and then check them. If you are the type who takes them off the heat and lets them acclimate naturally then your cooking times will be much different.
I read somewhere that adding salt and acids before boiling causes the beans to resist cooking. I don't know if it's true or how much difference it makes, but I always put the salt and vinegar in last because it takes fine tuning anyhow.
A word on the vinegar. I've had to use different vinegars in a pinch, but a good balsamic will give you far superior results. It really adds a nice complexity to the flavor.