what year model is the car?

did you open/tap into any existing wires?

did any fuse blow? (what location # and amp rating)

does the car have an alarm? is it stock or aftermarket?

did you wire in an amp?

you wont need to remove the spark plugs to test for spark, infact you should leave then in when you do.
when you crank the engine, does the tach bounce at all?
be very careful when testing for spark. really.