See panning can be super tricky because its orientation can be super wide , the panning process of a song depends on multiple factors , it can be a creative factor where panning can make the sound cool and experimental, or the flip side it can be totally about fitting in lot of instrumental channels together in a well defined fashion.
Panning is very important to add space to the mix and add wide range of tonality and spacial dexterity in it. You can use lot of hacks and tricks but the easiest way is to EQ the sound real well , mono the channel and tilt the spacial alignment here and there , feel the sensation and get on it , feeling is the key , Panning is more like a nice sitting arrangement of sounds.
Panning is something which comes later after gain staging because you gotta gain stage better in order to do justice with the signals, once the gain stage is right and post EQ, panning is good, panning as far as i know should be taken care of later.
Take care that you dont overdo the panning, keep the signals in centers if they sound great, dont over pan anything, because if you pan badly or lets say you go totally nuts on panning then the song will sound really off, i mean think about wideness, think about how you want to deliver each instruments, think about the space and how you want to distribute those signals in space, once you get it right, it will add so much of dimensionality to the song, but at the same time if you are just doing random stuff then it just make your song sound real bad.
Dont over leverage panning, use it only on those channels which require it, and if you over leverage it then it will just make the mix sound wavey, as a matter of fact you will lose all the tightness from the mix.