So what I have found is that aeration is 2nd to food.
If inclined, I might gather some of these things. Maybe some others will chime in too.
A base soil mix. I have been using a potting mix called Sunshine #4 Organic. Basically it is peat, perlite and hopefully a wetting agent and some microbial ingredients to help get things going.
A good compost. Can't say enough about this. Go organic. Coast of Maine Penobscott Blend is nearly perfect. Not sure why, but I have had good results.
Aeration. At least 30% of your mix should be something that keeps pockets of air in the soil. Perlite is generally the go-to. I have found that about 40 - 45% rice hulls work well for me. There is perlite in the above noted soil mixes and it helps too. Vermiculite is another go to, but I have never used it.
Additionally, there are certain nutrients that cannabis seems to like. Bat Guano, Kelp Meal, Alphalpha Meal, Lobster Meal (Coast of Maine) and some other goodies for conditioning the soil like organic gypsum, dolomite lime and Epsom Salt.
Other nutes may help, but I have found this basic mix works well.
Once it is all mixed, you should be able to squeeze it when its a little wet and it won't compress, but crumble apart when you let go. The roots will want to make their way through a loose, acidic, nute rich mix. Water and watch.
That's my soil mix.