Intermittent Starter ??

When engine is cold (> 1-2 hours), I turn ignition, solenoid clicks loudly but engine does turn over. After repeated tries, it usually will eventually start reasonable strong (not battery). Once started, or if warm it always starts easily. Just need some advise on what to look for or how to diagnose the problem. Starter? Solenoid? Contacts? Ignition Switch? Park / Neutral Switch? No idea of most likely cause or how to find it.

i had a 77 corolla that had the same trouble i fixed it by changing the battery to starter cable but i had to do it every three months the cable gets very hot also try putting something around yhe cable to insulate it