I left the trickiest part last: shoe/boot covers. They're a headache even at best. If a seam in the middle is a ok by the design and stretchy materials are an option you're mostly set, but what if the material you're working with is wool and only side seams can be considered?
Starting from the basics. First of all you need a pair of shoes you're willing to sacrifice for a cause, and they should match your reference pic shoes in shape as closely as possible. I was lucky to have this pair that I had walked beyond salvation that matches Talas' shoes heels, so I got to work.
I removed a band and a button that went over the toes of each, and because the buttons would not let go without taking a chunk of material with them I cut small, round shapes out of the straps and glued them in place. Else there'd be a weird dent each finished boot.
Then I painted the bottoms and heels of the shoes red - it's important to do it before the boot covers go on because painting as an afterthought may mean staining the covers.
Next I dug out a sheet and started figuring out how things should work. I used my actual shoe to draw the pattern both in correct toe shape and correct size and then continued the pattern longer to create the leg part. Don't even touch your real materials before you've got the pattern part right with the cheap fabrics! You want them to be just right, snug, but not too snug to go over the shoes and with the option of actually getting your foot in when it's time to put them on. When working on non-stretchy fabrics, especially if it's for a first time, make them mock-ups until they're right.
BEHOLD MY MAJESTIC LACK OF DRAWING SKILLS - anyway.
A) Shows how I used the actual shoe to draw the pattern. Just plop it on and trace around. A2) is the seam allowance, which I left at roughly 1cm, but sewed the seam actually a few mm on the outside of it, creating a little bit more room since the material did not stretch. Also see that you cut your other shoe's pieces as a mirror image to the first one.
B) The opening of the boot should be very wide and there should not be any attempt at making the ankle part snug. In Talas' this was actually just fine, since her boots are shown to bunch up a bit at the ankles.
C) Sew the side seams. Slip the shoe in carefully and mark where the heel will have to go through. Take the shoe out again. Cut a hole that's just a few mm smaller than the heel. Then cut 5cm straight up at the back of the heel, marked as a line on the C)-picture.
D) Cut a triangle out of your fabric and sew it at said cut. As long as it's a bit larger than your cut you're safe, you can trim the extra material off afterwards. Turn the whole thing around so that seams will be left on the inside.
E) The triangle will give the heel the extra space it needs when you work the shoe in again. After you've made sure the shoe fits snugly it's time to glue.
F) Preferably use fabric glue. It takes a while to dry properly (leave overnight just in case) but as the glue will be a bit stretchy it'll help your chosen boot cover material not tear in action.
Spread glue on the toe of the shoe and to its sides. Roll boot cover up, match the inside of the toe and roll cover over the shoe. Don't worry, the glue takes a while. You can keep adjusting for as long as you like.
The final shape of the shoe will be very open, so this technique won't work on boots that are supposed to fit tightly on you.
If you're going to embroider the boot cover it's best to do it before you glue it on. Much easier! Just see you don't pull the stitches too tight of the material will bunch up.
When working with felt wool you have one thing on your side: it does as it does. It doesn't stretch but it molds a bit according to how it's being worn. These boot covers were at first a little tight at the top, but after putting them on a few times they took the shape of the tops of my feet nicely.
But what if you need something else? Here are some tutorials I've found really handy. They come in various levels of difficulty ranging from anyonecando to holywowgrandmaster, so pick what suits your skills and needs the best.