Follow these guidelines before sending songs to be mixed and mastered

• BEAT:  if you’re able to get the beat tracked out, meaning you’re able to get the individual tracks such as the kick track, bass track, piano track, snare track, etc., you can also send in those tracks as well. (U can get a better sound but will add more time $$ to mixing) 
• Stems: Also you may have heard someone say “Can you send the stems?”, stems is just another word for ‘individual tracks”
• The most important (yet overlooked) thing when sending tracks for song mixing is making sure they are exported from the same starting point. 

• Label your tracks clearly! Names 

• There is nothing more frustrating and time-consuming for an audio engineer than to have to guess where each track goes and what is it.

• Each stem should start at the beginning of the song, even if there’s nothing on that track until halfway through. When the mix engineer imports the files into their DAW, they’ll line them up by placing each of them at the same starting point. If all the files don’t start at the same point, your productions won’t line up correctly. The mix engineer will have less time to mix your song if they have to spend hours trying to piece together the arrangement.

• 1 Song-only mastering:  just send the wave/mp3 stereo track (Don't send separated tracks/stems) This means u had it mixed already

• Sending your rough mix helps the mix engineer know what you’ve been listening to and what you want the mix to sound like.

• Send Clear Mix Notes 
  While different engineers have different things they want in mixed notes, the following are a couple of ideas to help you communicate as clearly as possible. 

  Keep all your mix notes in one place, like an email chain for each song. When you text your mix notes, it makes it hard to go back to the last round of notes and address those things. 
  Giving specific times for your notes is extremely helpful, particularly when describing specific events (ie. “Is that a pop I hear at 2:16?”).