It is quite difficult to make a balanced and effective fertilizer at home that will provide your plants with everything they need.
If you are interested in going organic, Bio Vega and Bio Flores made by Bio Canna are excellent products that I can highly recommend for you, plus they have been developed by a company with a huge market share and have done all the research and development for us, the consumers.
Egg shells are great to mix into the soil mix, but go easy on the coffee grounds.
You can make many types of teas/tonics for your plants, that will boost soil health and plant vitality, quite simply.
Things like wheat bran, malted barley, oyster shell flour, bone meal, volcanic rock dust, zeolite, kelp meal, worm casts etc are all excellent soil additives.
For recipes of home made teas and tonics specifically for cannabis, google "homestead and chill", they have excellent information on their website.
Hope this helps,........
Organoman.