One trick on vocals is to use 2 compressors in series. First a heavy soft knee compressor, driven reasonably hard so that the vocal is evened out (compression operating most of the time). Then a lively compressor hard knee after that, with a slowish attack and fast release so it lets through transients (compressing only on the peaks say). This gives back some attack and dynamic but in a controlled fashion.
Other than that, if it’s not standing out in the mix then it’s probably frequencies. It could be that there’s another instrument that’s in the way, likely to be guitar. Take out some instruments to see how this effects the vocals.
Finally, it’s a tried and trusted practice automate vocal levels during the song, to bring out various words or to dip consonants. Also automation of the other instruments too to keep them away from the vocals. This is what a compressor does but often they can’t do it so precisely.
Mike.