for chord variation, this video really helped me: https://youtu.be/ys0zXG_sZ4Y
it's a video on reharmonization but i found out from it that just swapping out chords in a progression for a diff chord that serve the same function (which is addressed at 3:00 in the vid) can rlly add a different kinda flavour without you having to do much
as for structure & where to place things, i have as much idea as you lol, however i do recommend 8 bit music theory's vids as they've taught me a lot about composition :^)
it's a video on reharmonization but i found out from it that just swapping out chords in a progression for a diff chord that serve the same function (which is addressed at 3:00 in the vid) can rlly add a different kinda flavour without you having to do much
as for structure & where to place things, i have as much idea as you lol, however i do recommend 8 bit music theory's vids as they've taught me a lot about composition :^)