Do all the usual diagnostic checks, like someone brought you a running engine that wouldn't start.
Use a timing light to see if #1 fires close to the timing mark when it's cranked.
Look into the carb and open the throttle 2-3 times to see if there is a good squirt from the pump.
Look at the vacuum gauge to make sure there isn't a big vacuum leak, or the cam is off by a tooth.
And so on.
