When working any type of magick it is important to record your experiences. It is useful to be able to refer back to remind yourself of what worked and what didn't. Also, think about how much knowledge we have from the past thanks to those how went before us and recorded their experiences, you will be adding to this.
You will probably find it easier to keep a number of them, possibly one for Rituals, another for Spells, even more for Dreams, Meditations, Pathworking etc. Although, you don't need to keep loads of note books, you can record everything on your computer and print out information when you need it. Whilst I don't condone taking other peoples ideas without permission, many Witches freely publish information on the internet which you can make use of. You'll find that "copy & paste" is one of a Witches most important tools.
There have been many discussions about what you should call these books, Gerald Gardner came up with the most popular name "Book Of Shadows", older books of magic are called "Grimoires", I call mine "Book Of Knowledge".
Rather than have a separate page, I will discuss "Magical Alphabets" here. They are useful when creating amulets and talismans. Some people also use a magical alphabet to write their books, this seems to be a good idea but it's one thing to write them out, it's another to read them during a candle lit ritual. Once again we must thank the magic of the computer, as most of these alphabets can be downloaded as "truetype fonts". These are the most well known, but there are others if you wish to do some research (after all, you can't expect me to do all the work for you).
RUNIC - THEBAN - ANGELIC/CELESTIAL - PICTISH - ENOCHIAN there are also EGYPTION - HEBREW - GREEK - LATIN.