I am new at this composition stuff. I have a melody with the right hand. I was wondering, on how I could get the left hand accompaniment without only using arpeggios and simple chords.

I wanted to make it sound a little more interesting.

The best way to make it interesting it so make simple chords or arpeggios with interesting rhythms. Furthermore, you could use alberti bass or something similar, you could use rhythmic simple chords, or you could form a counter melody.

Look at piano scores also, and study them. how the composer/arranger was working the left hand and how made it interact and connect with the right hand.

Okay, I'll try that. Thanks for your advice