A few tips that might help:

Reference often - multiple times an hour. With a reference track that is sonically similar to yours.

If you are doing electronic or hip hop or any genre where kick is the loudest element, try setting the kick to peak at -11dB. Turn down all the other channels to -64dB. Then bring them back in one by one, in order of importance (bass, vocals, leads, etc - will depend on genre) and set the volume based on the kick's level. Most important sounds will end up 3-6dB below the kick. Do this with your eyes closed, and you will find that you can place many sounds much quieter than you originally thought. This should build some headroom to push your whole mix louder.

Set a limiter on the master and make it so that the mix kisses the limiter here and there, but never does more than 1 dB (as you don't want to start colouring the sound too much). This will ensure you can compare your mix to your reference.

Reference some more.

Lots of pros use saturation and clipping and transient shapers and compressors to get loudness. Especially on drum bus.

Research using busses to add group processing, to help gel the mix together while making it sound louder. Common bus setups: kick and bass together OR kick and drums together (with bass on its own), FX, instruments (guitar / piano / etc), leads.

Kick and bass relationship has to be PERFECT or else they eat up too much headroom and muddy the mix. Some people spend hours perfecting the relationship.