Originally Posted by SouthArk370Z

Is the alternator putting out enough juice? Check the voltmeter on the top of the dash - should be reading at least 14 volts. Doesn't guarantee the alternator is OK, but it's a good sign if 15 volts or so.
Some auto parts stores will still check your alternator and battery for free. Grab the Yellow Pages and start calling.

Check the fuses and fusible links immediately next to the battery terminal. Use an ohmmeter or voltmeter; don't trust your eyes.

As per TreeSemdyZee, have you added anything electrically powered that is not turning off?

Check the water level in the battery. Add distilled water as needed.

Check battery connections and grounds for corrosion.

That's all I can think of right now. Good luck.