In addition to the main relay possibly being a cause --
Have you turned on your headlights and do they appear to be full-strength? If
not, try a jump start. Hopefully you just have a dead battery. How old is your
battery?
Next, carefully take the distributor cap off, have someone try to start the car
while you watch the distributor rotor. If it does not turning when you try to
start the car, your timing belt may need replacement.
When is the last time you changed your distributor cap, rotor, plugs, and wires?
All of these can be replaced at pretty low cost.
Next, check the distributor's ignitor. See
http://www.crx.org/southcal/tech/igniter/igniter.htm and
http://www.crx.org/southcal/tech/igniter/default.htm for help diagnosing this.
Last, suspect the distributor coil.
The Achilles heel of circa 1990 Hondas are the main fuel relay, the distributor
ignitor, and the distributor coil, roughly in this order. How many miles on your
car? When is the last time an ignitor was put on it? A distributor coil? Were
they OEM parts?
These are the typical ailments. Updates welcome. Good luck.