How often do you listen back to a mix and it’s good, but nothing grabs your attention?
You have added pretty much everything you can, so it’s not a lack of instrumentation.
More electric guitar? Too much already.
How about more drum fills? No space left.
More reverb, delay, and FX? Cluttered mush of sound.
This sounds like a perfect job for automation. If you've never used it, you are missing out. Automation has the power to take simple, up close vocal leads, into to a soaring wide open chorus and back again. Most every DAW has it, but not everybody uses it. Here are a few tracks I use automation on almost all the time.
If you don’t use automation on vocals, I would venture to say that your vocalist has the best mic technique on the planet and feels the vibe of the song. It is vitally important to have dynamics and create emotion within differing passages of a song. Without those subtle differences, it becomes sterile and boring by the second verse. As a very, very generic starting point, try taking the verse lyrics up a few db to make them closer to the listener and taking the chorus down a db or two in order to smooth out the overall levels. Use your ears, not your eyes.
Take a listen to almost any current pop song and you will hear only bits and pieces of delay on certain vocal lines. At the end of a phrase it is common to have 2-3 repeats of the last syllable or word. Create a FX buss (delay and/or reverb) and automate a send to that FX buss to taste.
3. Background Vocals
Most background vocals like to sit in a track at constant volumes throughout a song because they are not in the forefront. But don’t disregard them as being unable to add interest. When working with gang vocals, and I like to compare them to a live audience singing along. At first, they may be quieter and following along with the band at the beginning of the song, but as the song progresses, the audience starts to soar in volume and can at times even overtake the band. If the song calls for it, automating those tracks can be glorious.
If you are recording drums live, most often they don’t need a whole lot of automation if your drummer pays close attention to dynamics. But even for subtle dynamics, try raising and lowering the volume of the kick 1-2db for a chorus. That added energy would help to create emotion and then conversely, space, to bring the song back down for verses. Lastly, more often than not, MIDI drums are lifeless and without vibe. To bring that life back, randomize the velocity hits on the snare and kick drum hits.
5. Stereo Bus
As stereo bus automation can be easily overdone for impact at home, I would recommend trusting your mastering engineer to make those decisions. It is a delicate process that requires automation of about 1db in either direction. But often times, 1db is too much and you should only make incremental jumps of .5db at a time within the parts of a song. Like I have said before, use your ears not your eyes, and if it doesn’t add emotion to a song, leave it alone.