I know what you are thinking, what CGI?
Nearly all of Star Wars was done with models, matte paintings, travelling mattes and a whizzy new computer controlled camera called the Go-Motion. CGI in 1977 simply did not exist, not as we know it nowadays when it is absurdly easy to have a superhero destroy a city (wait, what do you mean you’ve seen that one?)
But computer animation did exist, albeit in a very limited way. A ground-breaking CGI sequence appears, almost un-noticed, in the briefing scene of A New Hope. The presentation is showing how they should swoop down the trench and attack the exhaust port. I confess I always thought that was hand animated, like the targetting computers, but it turns out it is pioneering computer graphics.
Here is a video (meaning actual, genuine, recorded on tape, video) of graphic pioneer Larry Cuba explaining just how he created that sequence.
Lucasfilm had a long history in pioneering computer graphics in films, even setting up their own division to investigate and do the work. They created the Edit Droid, the first computer controlled offline editing tool, which led directly to modern tools today like Premiere, and also pioneered computer animation and rendering technology. The rendering team made a few little films and characters, most notably the animated knight from Young Sherlock Holmes, before being spun off. You may have heard of them, they are now called Pixar.