Here is the audio for my house composition
Here is the video for my film composition
Here is the audio for my Alternative R&B composition
Soundcloud is good to use because others can discover your music, and you can see how many plays your tracks have and see how many people are listening to it at a time. Youtube is good to use as it gives your music a much broader audience to reach, and be recomended to people if they listen to music similar to what you make. Spotify is good to use as they have a good range of recommendations, as when people finish a song, songs similar to it start playing, and if your song is in a similar style to another song that someone is listening to then it might be suggested to them.
This is my college soundcloud page
You can add hashtags and a description as a part of your song. This can help it reach a certain targeted audience you are trying to reach. These people might really like electronic music if you labelled it as electronic, rock music if you labelled it as rock etc.
I personally use Apple Music instead of Spotify, and I know that there is no audio quality loston songs, if you upload it as a WAV file it'll play as a WAV, and same goes for if you upload an MP3 it will play as an MP3. There's also Loseless audio and Dolby Atmos on certain songs, which makes the audio quality even better.
I use Apple Music because I like the wide range of music you can get on it, for example, Frank Ocean's visual album "Endless" is an Apple Music exclusive, you can't get it anywhere else apart from Youtube where reuploads have been published. I also get suggested new artists to listen to on Apple as well
You can post teasers on social media of your up and coming songs. You can post 20 second snippets of your songs on TikTok, Instagram, Youtube, and Snapchat which gets your auience excited for when you release the song, and it can generate you fans before you release the song.
The music industry uses these platforms to reach an audience that might not use the big streaming platforms like Apple Music, Spotify, and Amazon Music. These audiences can interact with your music on these other platforms as a sort of different community other than the people that use big streaming services.