It's probably going to depend on what type of ignition that you have. For me, since I have a Mallory unilite ignition, they have specific steps to go through to check the components. These documents were available from their website.
One tried and true method is to expose the electrode on the end of the spark plug wire and hold it closely to a ground (the block for example) as the engine is running. You should see a steady electric pulse. If the pulse seems erradic, it could me a problem in the distributor or the coil.
Don't be quick to say a problem is ignition, unsync'd carbs can cause much heartache as well.
If you can give more specific details on your problem, I'm sure we can give you better help.
Good luck!