I think every designer has their own methods for documenting their pattern writing process and each has its pros and cons. When I first started out I would be working on a section, take a few cryptic notes and think that surely I would recall what I was doing in this moment to put it all in writing later. Pausing every few minutes to write down the action was time-consuming an annoying to say the least. The result was disastrous. Not only did I end up with incomplete pattern notes, all of that I'll-remember-later crap was the perfect equation for errors on top of errors.
These days I have two approaches that I use in conjunction to make my writing go as smoothly as possible. First, I have a pretty detailed plan of attack before I cast on my first stitch. This way, I can actually write out much of the pattern before I ever get started. I know my gauge, so I know how many stitches I need to cast on, I have my stitches selected in advance so I know if those stitch counts need to be altered, I have a rough schematic with measurements so I know how long and wide the pieces are going to be. I can get about 80-90% of the pattern down on paper before I even begin; this helps tremendously. When I begin knitting, I can then make adjustments as needed as I go. The easiest way for me to do all of this is by writing the pattern directly in word using the pattern template provided by the company I'm working with, or my own design template for self-published works. When it comes time to make adjustments, I track changes and keep detailed notes using comments. I will add a comment with all math equations for certain sections so that when it's time to repeat those equations, I have them easily accessible. For example, I was recently working on a semi-circle shawl from the top down and was calculating increases - the way I was doing this was taking the total number (t) and subtracting the edge stitches (e), then multiplying the resulting number (x) by 2 (y) and adding e+1 for my new stitch count (z) -> t-e=x; xx2=y; y+e+1=z -> and who said you'd never use algebra in your day-to-day life? Honestly, I failed algebra once and slept through it once so if I can figure this stuff out, I have faith that you can, too.
BUT, the point is that I was keeping notes on the calculations I was using so that the calculations could be repeated throughout the pattern. There are still going to be errors though, always, always there are errors. No matter how many times I go back and look everything over, as soon as I hand it off to the next set of eyes, there's an error jumping off the page. This used to infuriate me - and now, it's annoying for sure, but something that I've come to accept as a part of my humanity, a reminder of my very organic being that is fallible in an alarming amount of ways. This concept has been cemented for me over the years because after the editor puts their eyes on my pattern and makes adjustments, it goes to print and we all feel cozy in our ability to see and correct. Right up until some other eyes come along and start knitting. "What's going on with this stitch count? It's like, 14 stitches short." or "These sleeve decreases are doing something funny." And then I go back and see that there was a typo when the pattern went to print and that the corrections to the sleeve decreases that we discussed never made it into the final pattern. I tell you all of this now because if you want to design, you must be prepared to speak with the knitters of the world in regard to errata. It is a part of knitting life that sucks, but it can't all be wool sniffing and wine drinking, right? Where's the fun and adventure in that!? (and when I say fun and adventure, I do mean frustration and second-guessing nearing the point of insanity).
Now, my second plan of attack is similar in that I write out much of the pattern before getting started, but I use my trusty notebook. Each year I buy a fresh, new college-ruled notebook with dividers and I assign each section - maybe one is for self-published work, one is for published works, one is for proposals, etc - and I will use this in a similar fashion to going directly to the computer. I have all of the equations written down and detailed notes... but I do this for a pattern that is maybe a bit less complex - I can really just say to myself, "work st st, inc in patt 19 more times - 236 sts" and move on to the next section without all of the verbiage required by different companies. I can use my own short hand and make the process faster. I do, of course, then need to transfer that information to the provided template which can take 30 min to an hour. Related to this method, but still using the computer is using OneNote. If you have access to OneNote on your device, it can be a great tool for jotting down simple patterns the same way you would use a notebook - files can be organized easily and its user friendly.
Of course, there are tons of methods that designers use to work up size grading calculations also, and I've heard a great many use excel for this. I don't know if it was the excel class I had to take in middle school in the room with no windows where I felt like I was starved for air that makes me avoid the program or what, but just opening it with all it's wicked little cells gives me the creeps. If you didn't suffer some sort of bazaar childhood trauma, use it! Do what ever makes the process easiest for you! I just run my size grading calculations the old fashioned way with my brain and/or a calculator.
So, what about the basics... what does every pattern need? The most basic of basic is going to include sizes, yarn, gauge, needles, and notions. Sizing is one of those weird knitting things that even experienced knitters have to pause and really think about when it comes to knitting a pattern because each designer will write the sizing a bit differently. I have found that the best way to go about it is to list the finished piece measurements (like the sweater's actual measurement with ease) with the ease AND the wearer's bust size. So, say 40 (44, 48, 52)" bust worn with 4" positive ease to fit 36 (40, 44, 48)". This is wordy and most publisher's aren't going to phrase it like this, but it will save you a lot of emails from knitters that need clarification. For yarn, you will need to fill in the yarn used for the sample, including the weight, yardage, colors, and how many skeins used for each size but you can also suggest some other yarns that would be suitable for the project - maybe the yarn used is more luxury and out of the median price range of the average knitter, if you add suitable alternatives at a lower price point, your customers will be grateful. Gauge is usually very important and you should let your customers know if the gauge is worked flat or in rounds, what stitch is used to determine gauge (and if you read my previous posts in reference to needle material and its effect on gauge you can even say - wooden needles or metal needles or whatever), and gauge for each stitch used in the pattern if you feel it's necessary. I think needles are self-explanatory though it is important to mention straight, circular, double-pointed or a mix of the three. Notions, too should be included even if it's just a tapestry needle for weaving in ends. I find it's useful to mention under notions if there are multiple markers that will be used though - for instance, you may have a contrasting marker or a removable marker that will be needed and for those organized people that like to gather all of their materials before casting on, it will be helpful.
Schematics are tricky and though they're very useful to knitters, they can be a pain in the neck for designers. If you just search "how to make a knitting schematic" your're going to find a plethora of information - whether you are going to have the patience or skill to make your own computer-generated schematics? That's for you to decide. An alternative to computer-generated is, of course hand-drawn, but maybe that's troublesome for you also. The simplest way to add some measurements for your knitters it to simply list them! Find a good spot in your pattern - maybe with the notes or at the end, it's up to you - and simply list: Sleeve length from underarm X(X, X); Neck opening X(X, X); etc. What ever measurements you feel are important.
As with everything else that goes into pattern design, you will find the sweet spot for yourself and what information, how much of it, and how you want to present it in your own unique voice. Try to stick close to the standard abbreviations for where you live (they vary by country) and think about what you can add to your patterns that make them user friendly. Keep readability at the top of your list, but put your own spin on your template. When you get into published works, you'll be required to follow their standards and templates, so use your self-published patterns as a platform for your unique perspective.
This is where I leave you today, but as always I leave you with these words: