I would start by taking the plug out, and turn the engine over with a starter to see if you can get any fuel through the carb. You should see it at the carb throat. If not, then disassemble the carb and check the diaphram (too stiff or hard, replace), the float valve (I know its not called that) see if it moves up and down. It might be stuck. WD-40 through fuel passages to make sure they are clear. Its where I would start.
If fuel IS getting through, ground the plug and turn the engine over with a starter and see if you're getting spark.

Edwin