Write Down Everything
When you make even the simplest projects, keep records of what you do. It's better to have the information and not need it later than to want to remember what you did and not be able to. It's also helpful for when you pick up soaping again after a time away. Rereading the records you kept keeps you from having to reinvent the wheel.
You need a soap notebook as much as you need anything else on the supply list. You will refer to it again and again. It will be the record of your learning, the tangible steps on your road to mastery. A plastic three-ring binder works well. At first you just need some notebook paper, a pencil, a pen, and a dark marker. You can use the marker to write the recipe on a sheet of paper large enough for you to see it from anywhere in your work area. A good first addition is a plastic sheet protector. The plastic protector does just that — protects the paper from oily hands, soap blobs, and colorant.
If you make soap for quite a while and then stop, be sure to refresh your memory when you get out the soap pot again. Your first best tool is your own set of notes. Additionally, use this book and the other soapmaking books you've collected. You'll get the hang of it again in no time.
It is a nice extra to have a specially bound soap notebook. It can be a sketchbook in a gorgeous leather cover, a blank journal bound with pretty paper, or something you've made yourself that reflects your own style. Just be sure you don't use this treasure in the thick of soapmaking. Stick with plastic-covered recipes and disposable paper copies while you're working.
Keep a pencil and scratch paper within reach while you're working to record last-minute changes, substitutions, or inspirations. If your soap batch behaves badly, write down everything so you can go back over it to figure out what happened. Transfer what you've written to your notebook later.