I don’t think there’s a rule that it would be practical to follow. My gut tells me it depends on your vanishing points and the angle your´re looking from. Drawing ellipses correctly is definitely one of the skills that took me longest to master (and not sure I do master it) and it´s a crucial one....there are just so many circles in the world....
Some tools and exercises that help: take photos that have ellipses in them (not difficult: cars, laps, vases, an arrangement of cups and plates, anything) and trace the construction and perspective of each ellipse. It helps to see how distorted the ellipse is in relation to its axes (which is what you´re asking here about). There are ellipse stencils you can buy if you work traditionally and of course the ellipse tool in PS (or any other software) if you work digitally. My life changed when I learnt how to work with paths in Photoshop....You can create a straight ellipse and then transform it and skew it until it looks right. I can draw ellipses decently free-hand, but I´d say using digital shortcuts has helped with developing the “ellipse sense” a lot.

I miss sharing stuff on the forum...but at the moment all projects I'm working on are under wraps and I don't have time for personal stuff...Anyhow, this is a section of a spread I'm working on that I particularly like - sometimes I think that working under harsh deadline brings out my best work in that it limits my over-rendering tendencies...

I´ve had electronic devices around kids for the past 11 years - including iPads of every generation. It never seemed particularly difficult to keep them out-of-reach of tiny hands. Just find a spot in the house that the kids can´t reach - a high shelf or similar. If you put a loading cable there, it will be natural to bring the device back to its place to load after every use.
That said, we did have one cracked screen on an iPad once because my younger let it fall - but he was using it, so that´s a risk to live with if you let your kids access your devices. They are strictly forbidden to touch my iPadPro as well as my Cintiq and they never did - although it is within their reach.
My iPad Pro doesn’t run stable - especially with ProCreate. But that is most likely a device issue which I should have solved by bringing it back when it first occurred. Now it´s too late (and it´s getting worse and worse).

@demotlj one example of many: to map a pattern on a garment, following the folds etc...

Benvenuto! I was born in Milano, grew up in Italy, live in Switzerland and work mostly with the US
It´s a challenge worth taking and I wish you all the best. You may be interested in the life story of French artist Stephan Wootha. He also took a year to switch to art and the results are quite impressive. He gave a couple of interviews available on YouTube.

@burvantill They are super rough color studies and they are thumbnail-sized. If you zoom in you can see how sloppy they are. It takes me less than half a day to do them for a whole book - and saves a ton of work and headaches down the road!

I realize my process is modelled on what I learnt in vis dev....they are called "color scripts" and are routinely done for animation.

@davidhohn I don't think I can show stuff from my trade book just yet, but I can show a book I did last year for a super small imprint - I used the same process. The book launched this past August.

• Honing on character design: this is one of several pages with variations covering all main characters (the characters were electronic components...):

• Sketch dummy sample (I don't keep the thumbnails or don't scan them: I generally do them on paper - they are unreadable for everyone but me)
  
  This spread went through a bunch of revisions, but nothing major.
• Color comps. I send these because I found the major revisions at the final stage are on color (on the projects I work on as AD for corporate marketing), so I want to avoid that happening to me.

• Final spread:
  

@davidhohn Thank you so much!! This clarifies a lot. I think I don’t have experience of a serious editorial process. The majority of my jobs so far have been educational, where the art direction is very tight.
My first trade book (coming out in April next year) was a bit unusual because they had a big restructuring at the publisher while I was working on the sketches, so I had no contact and no feedback for more than two months. I ended up doing lots of alternate spreads - 2 versions of the same page - and when I finally had an AD taking care of the book, she basically just chose which of the alternates she wanted and made only very minor revisions.
I normally get into character design after thumbnailing and I do send in several character design options before starting to work on the illustrations. I also send in color comps just after sketch approval. So I do have other intermediate stages in my current process, but not two sketch stages. My refined/final sketches are done directly after thumbnails and take about 2-3 hours per page. I guess there is a lot of variability in the process!
Now I know what to do if I get to work in a more collaborative ideation phase - I do hope my next job will be a trade book again, with a stable AD!

There no shortage of work out there and even the agents I work with from the AD side say that they’re getting more enquiries. One even speculated about the return of a “golden age “.
I’m just at the beginning, so I could definitely welcome better paid work (especially so that I could leave my contract job), but I’m getting a ton of educational work right now - probably more than I should take. This past year was quite healthy.
I’d say if you’re not getting traction you either need to revamp your portfolio or change rep....