This is covered in many of our mixing and mastering tutorials.
What DAW are you using? We have tutorials which focus on how to mix and master your tracks specific to that DAW.
What you are essentially looking at is how to use a brickwall limiter in the mastering stage. This increases the loudness of your track, and also has a ceiling set so that the audio doesn't distort or clip when you raise the input volume. But there is a tradeoff. The more you increase the volume, the more you lessen the dynamic range of the track. So don't get too caught up in the loudness war. Brickwall limiters can give you about 6-8db of gain increase without altering the dynamics too much. But it all depends on how you mixed the track, through to what processors you have applied in the mastering stage.
Let us know what DAW you are using and we can recommend specific tutorials for you to watch