Write Something with a Big Transition
Here are a couple ways to approach this challenge:
1. You could think of it as a position transition. For example, this could be a jump from the 3rd fret to the 12th fret in either your melody or chord progression. For example, if you're playing a D Shape D Chord down in open position, you could write a progression where you zoom that shape up to frets 7&8 for that G chord. To be more general, write something that takes you up and down the fingerboard.
2. If you like writing lyrics, write about a big transition in your life.
3. If you want to be more etherial, think of the big transition as a transition from one section of a song to another section. Maybe the first section is playing low low bass notes, the chord progression is also using low voicings, and the melody is using lower notes. The second section could be an explosion into a higher register for each instrument, creating the effect of "woah that was a big transition from one section into the next."
Remember, keep it simple. Good music does not equal difficult music.