[KimMG]

First you need to check to see if your battery is holding a charge. Use a meter to check the battery, voltage should be about 12.5 volts.
Check to make sure all the connections to the battery are clean and secure.
Make sure the ground cable from the battery to the body has a secure, clean connection at the body.
Make sure the connections at the starter are clean and secure.
Check the connections to the alternator to make sure they are secure and clean from corrosion.
Check the alternator belt.
Check the output of the alternator. When you measure it with a meter, it should read about 14.5 volts

After checking the above and you are not able to isolate the problem check back.