I’ve seen others’ lists that are much longer, but there are only two main things I would really have liked to know when I first started knitting.
There are different ways to cast on
I was taught with the backwards loop cast on. Just the backwards loop cast on. I HATE the backwards loop cast on.
It is easy to do, and it is easy to remember how to do. It is not, however, easy to knit that first row. The first few stitches go fine, but you start to get a little extra yarn between your needles. With each stitch this bit of yarn gets longer and longer until the cast on stitches are loose and hard to manage.
If you only need a couple of new stitches but need a not noticeable edge, backwards loop can be your friend.
These days I default to the long-tail cast on. It has its own problems (like trying to estimate the yarn tail so it’s not too long or short), but it is easy to start knitting on and looks quite nice on the cast on edge.
Between those two I used the knitted cast on or the cable cast on (they are similar), which are both easy to do and easy to start knitting from. I still use these when I want to cast on in the middle of a row, if the edge they create won’t cause a problem.
We have access now to so many different types of cast ons. They have their own uses, advantages, and disadvantages. It’s good to memorize a general method and have a reference available for when you need a special cast on.
Not all knitting needles are 14″ long and not all needles are made of aluminum
I used my mom’s knitting needles when I first learned how to knit. She still has them, a full set of 14″ long aluminum pairs of needles in a nice case. I hate using them. They’re awkward, especially for a larger project, and very slippery.
When I first tried double pointed needles, I got 8″ long aluminum needles. The length is okay (for me), but aluminum is slippery. I constantly had needles falling out of my project. It was irritating.
At some point I discovered bamboo needles. These are great! They’re not so heavy and not so slippery, so now they only fall out of my project when there is only one stitch on them. (There’s still no cure for pulling the whole needle out thinking it’s the empty one!) I use bamboo DPNs all the time now, even for flat knitting if the project isn’t too big.
And then I tried circular needles. These are great because your project can be huge, but instead of hanging awkwardly to one side or the other, you can put it in your lap. You can also find them in a variety of lengths, so you can even knit blankets in one piece.
I’ve tried nickel-plated needles, which feel nice, but I have not personally found a use for. (I hear they are great for lace though.)
The needles themselves even come in different shapes than round, like square and triangular.
There are so many options you should be able to find needles that fit you and your projects best.