There are many causes fir this. Start with the most simple to the most complex when diagnosis anything through the pricess of elimination:
1- check battery condition, make sure you have a good static charge of 12.4 or 12.6 V when car is off. Check battery terminals to see if they are very dirty, corroded or loose. Follow battery cables to main source make sure no corrosion. Check negative or ground cabke follow to source make sure the other end is tight and clean..
2- inspect ignition switch for problems.. Sometimes car dies inmeduatey after turnibg on, typical of thus priblem
3- check ignition system: distributir coil, and igniter, cap and rotor, moisture can get there causing short curcuit.. Check with spark checker and look for spark
4- Check fuel injectors, maybe clugged due to carbon build up.. Replace them if necessary
5-- check for bad fuel filter, dirty or clugged.. Bad quality fuel.. Could also be an issue.. turn key to on position, you should hear a buzz sound indicating fuel pump is priming.. Check for fuel pressure, loosen bolt on fuel filter, then turn key to on position only, you should see a squart of fuel coming out.. If not, you got a problem.. Before checking fuel pump, make sure its not the fuel filter bad, causing fuel pump to workmore than normal. Very careful, never check for ignition and fuel system at the same time, very dangerous. never smoke when checking for fuel pressure.. Install fuel pressure gage into fuel rail, start engine and see pressure then compare to manufactures pressure.. Hope this can help you..