Noel Gallagher writes guitar parts that are physically large. Big open chords, every string ringing, a relentless eighth-note downstroke that takes care of the rhythm by sheer weight of effort. That sounds like a lot for a beginner, but the chord shapes themselves are almost all open-position basics: C, G, Am, D, F, Em.
The descending bassline trick on Oasis songs
The trick to most of the catalog is recognizing the descending bassline. Wonderwall does it. Don’t Look Back in Anger does it. Half the World Away does it. The pattern moves a chord shape down from C to G/B to Am to F, and the bass note is what gives the song its forward momentum. Once you hear that move, you start spotting it everywhere in popular music.
If you only have Wonderwall, your next Oasis song should be Don’t Look Back in Anger. Same vocabulary, same rhythmic feel, slightly more chord changes. After that, Live Forever is the one that builds your right-hand stamina, because it asks for sustained eighth-note downstrokes through entire choruses.
What’s worth borrowing from Noel’s playing is the commitment to the strum. Beginners tend to soften when they get to the chorus, anxious about not making mistakes. Oasis songs only work if you keep hitting the strings with the same force throughout. That builds the muscle memory you need for any rock song you ever want to play.