I would add some salt and rue to your bath.
Rue comes in the form of dried herb leaves --
Rue Leaf (Ruda, Ruta)
Rue is also available ready-mixed with salt in the form of Rue Bath Crystals:
Rue Bath Crystals
Hyssop only targets negativity that you have brought onto yourself through your own actions, or "sin". It's not the best choice if you are dealing with any sort of residue from contact with other people or situations that have drained you.
Rue targets negativity brought onto you by others - it's been used for a very long time in Europe as a cleanser of the Evil Eye. Pray over the salt that it will cleanse you in body, mind, and spirit. Salt can be a powerful general cleanser when put that that task.
Generally spiritual baths are standing/pouring baths, not soaking baths. So, yes, take your normal shower to get the regular dirt off, wash you hair/body, etc. Then prepare and take your spiritual bath. If you're using a bathroom that has the shower/bathtub combo, then just fill the tub to ankle deep, add your bath salts or herb tea, and then do your pouring bath..
You only need a bit of water to dispose of at the crossroads - I usually take about half a water-bottle full. Yes, the rest of the water goes down the drain. I usually then rub salt around the tub afterwards to cleanse it.
Which way you throw the water depends on the purpose of the bath. If you are drawing stuff to you, then you throw to the East/rising sun. If you are getting rid of stuff, then you throw to the West/setting sun.
I have not heard of the mirrors being covered. I know Jewish people cover mirrors for a period of time after a person had died, but I haven't heard of it in conjunction with hoodoo bathing rites. Perhaps someone else can speak to that. It's certainly not something that I have every been taught to practice.
Devi Spring: Reader & Rootworker - Proud AIRR member and HRCC Graduate.