Engine's need Spark (at the right time),Fuel and compression to start.....
so i'd start by spraying starting fluid or flammable brake parts cleaner straight into the carburetor (or remove the spark plug and give it a burst or two in the plug hole) and try to start it. if it runs and dies, you have a fuel delivery issue. if it doesn't fire on starting fluid, i'd suspect no spark, and then check for spark, first at the end of the end of the spark plug by grounding the electrode to the engine block/metal. if no spark that way, get a screwdriver and stick into the plug wire and touch the screwdriver to metal on the engine, and see if you get a spark jumping around,