Part I
Star Wars was far from alone in leading a revolution in special effects (FX), contemporary films like Close Encounters of the Third Kind, 2001, and Irwin Allen's various disaster films also pioneered films that accorded a prominent role to their effects work. But Star Wars was in a class of its own for combining multiple types of FX ranging from miniature work, makeup, sound design, and a bevy of other FX into a coherent whole film. One way to see just how revolutionary Star Wars was for FX is to contrast key scenes of Lucas's film to major FX scenes from the Academy Award winners and nominees for FX work from the 1960s and 1970s.
(note- some of the SW clips I'm going to use are for comparisons between the originals and special editions, which further illustrates the evolution- or deevolution- of FX work)
One of the things SW was justly famous for was the quality of its miniature work and blue screen composites. SW models often moved in a highly dynamic fashion, much akin to actual planes or other real world vehicles. Take for example the Mos Eisley escape scene (starting at 1:25). Not only are their composite shots of Stormtroopers wathcing the takeoff from Mos Eisley, the scene features a planetary escape, interception by two Star Destroyers, and the Falcon's maneuvers before it escapes. None of the models in these shots are static or center frame; they either move from the bottom of the screen or the corners and move towards a focal point. Now contrast the Mos Eisley escape to 2001's Blue Danube scene. The basic structure of both scene are similar- model spaceships leaving orbit and interacting with other models. There are also similarities in editing and the use of musical score to set a mood (upbeat Williams brass for adventure, Strauss for leisurely space waltz). Kubrick naturally knew to put effects off center and have them move towards something to create a dynamic scene with a stationary planet in the background to underscore this. But 2001's space ships and satellites are much more placid than the SW's journeys into space. The docking scene of the Pan Am space clipper starts at 2:55 and lasts nearly three minutes with quite long takes of the models in motion. SW's cuts were much shorter and more dynamic. This evolution was itself a legacy of 2001 which pioneered a number of elements of motor-controlled camera rigs. Lucas's FX team under John Dykstra, himself a veteran of 2001's FX team, had the advantage of using motion-controlled cameras system that used computer inputs that gave the appearance of genuine camerawork. While 2001's model work demonstrated the efficacy of this system, SW's FX work showed the potential of a maturing system.
This trailer and this clip of 1969’s Marooned demonstrates how exceptional 2001’s use of movement in space was for science fiction films of this period. Aside from using stock footage from NASA, the models are undetailed, center-framed, and static. These clips from Marooned also show a tendency to separate out FX shots from scenes with human actors and seldom integrates them. The 1971 Disney film Bedknobs and Broomsticks likewise shared this tendency to segregate live-action from FX, such as this scene where a magically-animated museum pieces take to the field against the Nazis. When FX and actors interact, it is obvious the armor is a man in suit or a jouster on wires, the disincorporated Highlanders never face their Teutonic enemies. This is quite different than SW’s holochess scene which not only features small-scale stop-motion composites of the chess monsters, but also features them in the same shots as the droids, Han, and Chewbacca. Not only did this normalize multiple types of FX - stop-motion, Peter Mayhew in a wookie suit, and the droids- it had the effect of normalizing this extraordinary composite of different FX. While Bedknobs and Broomsticks went out of its way to signal the novelty of its FX to the exclusion of everything else, SW did something more novel and treated FX as part of the scenery for a minor character-building scene. This use of FX as a vital component of world-building was something that even contemporary critics of SW like J. G. Ballard acknowledged.
Some of the pre-SW effects work could be quite technically good. The capsizing scene for 1972’s The Poseidon Adventure is a very well-edited use of miniature work, camera cinematography, and set design to create an illusion of a luxury liner turning upside-down. Yet none of these FX shots are directly integrated with each other. This scene has three basic components: the captain and crew, the party, and the liner model. The scene sets up a clear narrative of cause and effect, but in a pastiche of different FX. SW in contrast often blended effect shots together. Take the escape pod scene at 7:00 Not only does the pod launching show the dynamism of motion-controlled miniature work, it also features FX shots composited into each other. The imperial gunners see the pod and their turbolasers track it from outside their window and the droids also see the star destroyer spiraling away from them. While there are clearly flaws in SW’s juxtapositions of multiple effects, placing FX shots together was something new for audiences in 1977.
SW’s used future aesthetic was also something that was quite unprecedented for SF movies of this period. Although dinner at the Lars homestead features very 1970s Tupperware for the blue milk, Lucas and his team were quite willing to ensure that the sets and other props had a distinct look to them. This attention to minor details was rather atypical for SF, which often repurposed existing buildings and structures for future settings. An extreme example of this was 1975’s The Hindenburg’s climax intercut set footage with newsreel footage of the blimp’s explosion. The film incongruously shifts to black and white from color so that the newsreel footage can be incorporated directly into the film. Marooned also used found footage and this was a staple of much SF of this period. 2001 allegedly did not get a nomination for makeup for its primates because Academy members thought they used real apes. These often date older SF as products of their time rather than visions of a future. Logan’s Run, for example, shot several key scenes like this runner shoot-out in the Dallas Market Center shopping mall. Such real-world locations not only dated the film, but were also showed a discrepancy between the purpose-built sets which were quite flimsy and cheap-looking, such as the arena seating for the fiery ritual of carousel. The latter’s wire-work may have been impressive, but the pristine arena is clearly a set. Other Logan’s Run sets such as Logan’s apartment are relatively spartan aside from its futuristic deco, which was only as strong as its set designer. Such bare walls and future lighting is a strong contrast to the interior sets of the Death Star which are often busy and convey its technological terror even if it is never clear what purpose such décor serves for the space station.
SW’s set and prop design, a good deal of which owed itself to the vision of Ralph Mcquarrie’s concept art, really distinguished it from other SF of this period. Logan’s Run’s mishmash of future and present was not nearly as coherent as SW’s. Added to this, a lot of pre-SW FX work was pretty cheap-looking. Logan’s Run featured a robot that looks quite pathetic compared to the variety of droids on the Sandcrawler. Even though the mechanics for the FX were the same for both- an actor in a suit- Lucas was less willing to compromise on his vision for the droids in the name of expediency. Both Kenny Baker and Anthony Daniels noted in interviews that the experience of shooting SW were quite grueling in the droid suits. Other little details, such as the specific com static of each of the fighters in the Battle of Yavin helped impart a degree of veracity to the fantasy that was not present in prior films. Although the original panoramas look rather dated, they are far more detailed compared to Logan’s Run’s monorail scenes through the City of Domes that look like an elaborate HO railroad diorama.
I don't know much about this myself (and I'd love to learn more!), but here's an old thread about Star Wars as a cultural phenomenon where /u/rocketsocks, /u/crosscanyon, and several others touch on the special effects among other points. Hope it helps!