Everything I will say comes from personal experience, which isn't transferrable, and reading books like Lee Parks' Total Control.
According to his advice, to brake even in the most controlled situations, you should apply the rear brake before the front brake. This maximizes braking AND grip, avoiding accidents such as yours.
From experience, if something undesired happened and you don't know what you did wrong, it's very likely you have done something wrong, and being conscious about it and trying to figure it out is a great symptom that you care and want to improve to not do it again.
Maybe your mind wandered a bit and you hit the brakes just a bit harder than you think. The street conditions you describe are worse than pouring rain, because the drizzle mixes with dust and oils in the tarmac making it very slippery. Heavy rain washes all that residue faster.
I'd give lee parks' book a shot, you will learn the technical aspects of why your accident actually happened and the correct technique to avoid it.
Drive safe, and heal soon!
Sign up for a CHP riding course. Start reading https://www.amazon.com/dp/0760343446/ref=cm_sw_r_cp_apa_glt_fabc_3K0PQDXHGP8PYN3N1XDF
Ride on empty back streets with no cars. After you start getting more confident, you can graduate to busier streets. Take a break and relax. Don't force yourself to ride. You should feel confident and clear minded before getting on.
I will defer to /u/ViperThreat.
I will say is that having a professional watching you in-person and giving you instruction is always going to be the best way to learn. They'll be able to catch things that you're doing wrong and help you reinforce what you're doing right.
If you're a fan of reading, I suggest checking out Lee Park's Total Control. It will help contextualize a lot the things that you'll learn either on your own or from others.
No no. Of course not. Like others have said, you’re not going fast enough on the street to be able to hang off that much. Not enough centrifugal force and such. But a little butt slide off and leaning definitely helps on street level riding. Going 60 km around a corner, you also need less weight shifted off Center to achieve optimal tire contact and lean angel. If you’re taking that same turn at 130km you obviously need to move more weight off center, hence more exaggerated “track” shape. But the steps and things you move are the same.
On the street you should open your hips when you turn a corner, slide off the seat a little, etc etc. How much all depends on speed and degree of the corner. I think most people here can agree on that.
This is the best book about performance riding on the street. There’s also a course he runs as well. Highly recommended.
I think you'll find head positioning is guided by where your looking which is absolutely key. You want to be looking where you want to end up and if that involves moving your head then you should be doing that.
His head turned to focus round the corner to the furthest point he can see, tilted to level view against lean and while he's not at an extreme position his head is just about on the centerline.
Have you tried reading? https://www.amazon.co.uk/Total-Control-Performance-Street-Techniques/dp/0760343446 which will explain the body positioning and the reasons why it works.
This is the danger of asking a load of rando's on the internet with unknown motorcycle history or ability.
There is some use to hanging off on a public road, but that benefit is generally around keeping the suspension more upright (working optimum) and not going faster or leaning to the edge of your tyre.
Just shifting your but and ducking your shoulder to the inside will have enough of an effect on the road.
Keep in mind on the road you want to use techniques to reduce risk and improve your margin of error, not reduce it.
There are places doing courses of what you are interested in, maybe invest in learning the skills from someone or read a book explaining the physics.
https://www.amazon.co.uk/Total-Control-Performance-Street-Techniques/dp/0760343446
https://www.circuitbasedtraining.co.uk/motorcycle-training/advanced-cornering-385