Whenever I export a song and play it on normal speakers (phone, laptop, etc.), the high end is sort of there, but the full body of the song is lacking in a huge chunk of the high end, and as a result doesn't sound clear enough to be sonically satisfying. I've done some searching around and lots of sites say that it can be caused by a build up of low-end freq. in instruments that don't have much purpose in that area. I do narrow cuts accordingly in my mixes, but my songs just can't push their way into a fully clear sound on commercial speakers. Any tips/solutions?
As @ibonyun is saying in his comment, very often, the problem here is the monitoring. When a mix sounds acceptably "fresh" on your monitors (no matter if headphones or speakers) but lacks the freshness on other systems, your monitors might simply be emphasizing the highs too much.
One thing you can always do: use reference tracks, over and over again. Think of a great sounding song. It does not need to be too similar musically, but the genre should fit and the overall sound should fit. Think of: "If my mix could sound as good as... (this reference track)." You might observe, that your reference tracks sound a bit too crisp on your monitors, which again then will confirm the hypothesis above. Use different reference tracks.
Another thing you can do (but this will cost you some money) : use a specialized tool on your monitors that compensates for crispness (plus other sound issues). Sonarworks has a good one that is widely accepted.
If you don't have the money for such a tool, you can try to compensate by using an EQ setting right before your monitor's audio output yourself. This may end up in a bit of guesswork, and the results may still lack in terms of quality, but perhaps you will improve at least a bit. A high-shelf dip with a wide Q might be the way to start. Use gentle settings, a little less gain compensation might help more.
Also, some monitors themselves have options to set highs and lows on their back. This is similar to using an EQ, but just inside the monitor's hardware.