The fuel pump would be the first thing I'd check. Take the vacuum line off of it and have someone pull it over while you check for suction with your finger. That will tell you if there's a really bad vacuum leak, but not about smaller ones. The pump will probably have to be rebuilt every couple of years
Then try pressurizing the gas tank to see if the lines are clogged. I once forgot to open the fuel on/off switch. There should be a steady stream of gas out of the fuel pump discharge side.
after that, you can try putting about a tablespoon of gas inside each cylinder mixed with a little oil. It should fire right up and it might be enough to get the pump going.
and also, try cleaning the carb. That's also a very common issue.
Try pushing fuel through by blowing into the gas tank. Some people just blow into the vent line, I usually just cup my hand around the gas fill hole and use an air compressor. You should see fuel moving through the line. That will instantly tell you if there is a clog.