My '72 ElDorado's showing her age. The front hood now lifts
off its place on the left side. The streaming air underneath lifts it,
while the right side remains, more or less, aligned with the rest of
the body, as should be. I have to get out and slam it down. Most
of the lift occurs closer towards the windshield side.
It rises a good few inches.

How do I go about adjusting the hood?

 

Sounds like a bad hinge or bent hood, not uncommon with a car this age. Could also be a bump stop out of adjustment. These are at the front of the car on the header panel. They are threaded with a large rubber bumper on top. To lower the rear or the hood raise the front bump stop. You may need some liquid wrench and a good set of channel locks to adjust it. It will be trial and error adjustment.