clean the battery connections.

 

This could be alot of things. If it is a clutch model and you are depressing
the clutch fully and it sometimes doesnt start, the bottom line is to
see if there is power at the starter terminals under the car-- right
where the starter is wired in. Best to have a mechanic do this on a lift.

If you have headlights, you could suspect the little switch behind the
clutch pedal, the starter itself, or most likely a starter relay located
in a compartment behind the drivers side wheel-well ( behind the
mudguard (driver's side).. Sooner or later it will quit altogether
so the cause will be revealed.

 

To add to marc z's answer...If you have headlights and are getting nothing when you turn the key..Check the main fusable link. If the fuse is broke it could make a connection if it is moved just right.. explaning why your car works now.. If it is the fusable link make sure you find out why it was blown before putting another one in.
Good luck.

 

Thanks guys! I will check on those.