What's "too many" instruments? You just need... MOAR COWBELL!!
Presumably, you're adding these instruments deliberately and they have purpose in your music. I don't see any reason to curtail that behavior. Just organize them in the mixdown.
If you're going for a "wall of sound" style mix, simply spread them out in the stereo field to create a fat, wide stereo image. With a lot of mid-range instruments, position them in some logical fashion... i.e. lead voices / instruments dead center & present (12:00), support & harmonics (10:30 & 1:30), etc. Panning will place them left & right (x axis). Use gentle EQ boosts to lift (highs) and lower (lows) sounds (y axis). Use volume and "effects" for presence (z axis). Use compression to "pin" an instrument in space and give it priority in that spot. Compressed sounds are less susceptible to being masked.
If you have reverb on your percussion, use a noise gate on the reverb to tame it. You'll have more room for instruments. With reverb on instruments, shortening the decay time and adding some pre-delay can open up a mix.
Also, it helps me to establish a "back wall" in the z-axis... the softest level before something sounds like unintelligible noise, and think in levels (6 usually) up to the loudest sounds on level 1. The levels don't have to be rigid (the human brain will pick out level 2.3 from 2.7 just fine), it's just a guide.
Great voice, btw!
Solid response and well thought out due to experience.
I honestly don't have very many components to my song. Drums (drum set with or with out toms), Bass (sub+audible bass), Leads, Chords. I focus on getting those elements down for my music, then i look into adding layers for the bass, leads, chords, or percussion. Which eventually leads to sound effects and transitions when i have the music.
Like what the quote says, you can spread out your layers and/or decide what has purpose.
I would suggest you get the foundation of your song strong, then focus on what could be added rather than going all ADD and just doing what ever you want. Eventually you'll have to come back to organizing it if you want to make sense of it all.
Which to my point is about book keeping and purpose in your sound and creation.
It sounds like your the opposite of me when it comes to making music. I am just trying to get a right balance of musical expression with the components i have in the mix with out adding to much. You might go over board with ideas and eventually get slammed when you catch yourself. In that case, your way is fine, but i'd suggest more self control and mindful behavior. It will enhance your natural flow if you're, once again, taking a step back and focusing on the phase of work you're in. And if you aren't to keen on yourself, i suggest you start practicing that self awareness. Plus it might lead into other aspects of your life and make that better too!