1995 Chevy Lumina Car will not start

Engine Mechanical problem
1995 Chevy Lumina (4 cyl not sure), Front Wheel Drive Automatic 66,000 miles

I have a chevy lumina, 66,000 miles. My car only starts when it wants to. I put the key in the ignition, turn the key past run, and the engine does not start. The radio and dashboard lights will come on, but the engine does not start. No clicking noise happens at all, the car seems dead when I try to start it, only the radio and dash lights will come on. The battery was bought in July 2008, and the cables connected to the battery have been tightened and cleaned. After 5-10 times of trying to start the car, the engine finally starts. But it seems that I have to hold the ignition key longer then normal when my car finally starts. The cars start in the mornings before I have driven it, but once I leave for my destination and get back in the car to leave, it won't start. I don't know if it has to do anything with the car being warm, and that is why it won't start. I am lost, please help!
Thanks