Rhythm guitar is all about playing chords, it is about how you play your chords ( what kind of fingerings you use—voicing is the correct term here—-) and what kind of rhythm you use for playing those chords. Simple eh? Most beginners need to work first on getting their chords clean. As they work on this they may ignore the rhythm of the chords. Okay I understand, as there are so many things to think about in the beginning. The key is, being aware, being aware of the songs you listen to, What goes on music wise? What makes those songs sound the way they do? In most cases it is the rhythm, it is the way how the chords move from one chord to the next one and how those chords gel with the bass line, melody and the drums. All of this is called the groove, most beginners need to work on this, even more experienced players will often benefit from concentrating more on the how the groove is being played in a particular song.
A good way to get into the zone of what a good groove can sound like is to listen to some old Stax and Motown songs. A lot of the recordings from this period were played by the same group of backing musicians such as Booker T and the MG’s. If you are not familiar with some of the music from this period (late 50s till early 70s) check it out as you will pick up a lot of ideas from what you hear.
Rhythm guitar is often overlooked, some people may even think it is a simpler form of playing guitar since playing single note solos is a more exciting sound. The truth is: Rhythm guitar is the start of your playing, the better you understand it the better your future solos will be.
Once you start playing with other people it is useful if every player can hold the rhythm. In a band (or any collective form of musicians) any instrument should support the rhythm, if this is not the case the band will not be as strong as it could be.
I mention all of this to support the idea that playing rhythm guitar is as much fun as playing guitar solos. Listen to a lot of different music to get a good idea of what is possible and experiment with your own playing to get some of those sounds under your finger tips.
Happy playing and hope to see you soon again,