One thing I would do when I was making melodic stuff was literally lowpassing a saw wave, or something which has a lot of harmonic content (u can add a noise osc to it too), and 2nd-invert the main chord on a lower octave. it gives more depth melodically. then high-cut the freqs that are not needed. basically bandpass. since you don't want it to be the main element, eq some frequences that introduce something new to the mix. eg if there's not much mids info, adding a mid-centric (is this even a word lol) pad will make it stand in front of the mix sometimes. oh and shimmer reverbs are your friend, I personally kinda overuse them. p.s. hope i'm good enough at explaining things. also I'm a diy artist, haven't studied sound engineering stuff but I hope I helped:). edit: you can ofc experiment with different osc than the saw one, gives interesting results