Developing visualization skills?

I've talked about this a little in a few discords and thought it'd be better to ask here.

I'm trying to work on developing my visualization skills to make drawing from memory that bit easier and I'm looking for a few tips to help improve those skills. There's no shame in using refs I know but I'm not always going to be in the position to make selfies to use as a ref or pull them up from online sources failing at selfies.

One thing I find particularly tricky (and it's probably key to developing good visualization skills) is observations and knowing what to look for in the first place. I'm not always sure if I'm going in the right direction or if I am on the right track and I'm just second-guessing myself too much which I am prone to doing. Either way, tips welcome and appreciated!

What I'm doing already:

1. Studies - always from references to warm up before drawing from memory to test what I learnt. I'm essentially using references to learn to draw without a reference. I do a batch of 12-14 studies about 3-5 mins each from a mix of topics - sometimes it's gestures, sometimes it's specific body parts (I did a batch of hand studies recently) and sometimes it's clothing folds. I vary things up daily which brings me onto a question. Should I be focusing on one topic for longer rather than bounce around as I currently am - would I benefit more if I did say gestures for 2 weeks straight before moving on to the next thing I want to work on? I genuinely don't know the best way to tackle study art and I'm kinda winging it.
2. Anatomy - Mostly doing quick gestures looking at how the body can move and how limbs distort in different angles. Mainly started these to get better with posing which has started to help!
   1. I colour code muscle groups when doing gestures to help things to stick to mind - I'm visual learner
   2. When drawing from memory, I use mannequins to build up sketches more often and lay down basic muscle groups on top that - even if I don't need it in the finished art it's more for practice and reaffirming what I learnt doing gestures. Sometimes I start the body with that flour sack they use in animation exercises and use rhythm lines to build up the anatomy instead
   3. As I'm doing gestures I'm thinking about how the pose flows and how shapes relate/connect to each other to make building a more fluid mannequin from memory easier
3. Clothing folds - I'm identifying types of folds and looking for how and where they form as well as how they wrap around the limbs/body