Here are some things you'll need beforehand:
- A phonology
- A few words
- Something to write with
First, you want to start with what type of writing system you want. There are a few different types to keep in mind, such as:
Alphabet
This is what English uses. In alphabets, consonants and vowels are treated equally, with symbols corresponding to sounds. Some examples of this include the Latin script, Cyrillic, and Armenian script.
Abjad
An abjad is similar to an alphabet, however, it is usually written without vowels. There might be optional vowel diacritics used, but usually, words are written without vowels. Examples of abjads include the Arabic and Hebrew scripts.
Abugida
Abugidas, also called alphasyllabaries, have their vowels attached to the consonant with a diacritic. Examples of this include the Thai script and Devanagari.
Syllabaries
Syllabaries have a symbol for syllables of a word instead of individual phonemes. These can also represent mora (more info: https://en.wikipedia.org/wiki/Mora_(linguistics)), such as how Hiragana and Katakana work. Some examples include the previously mentioned Hiragana and Katakana, along with the Cherokee script and the Vai script.
Logographies
Logographies have a symbol for concepts, where words are usually one or two symbols. These scripts can get up to several thousand characters, and as such logographies are especially challenging to design. However, most writing systems are descendant from a logography, so this might be a good way to make your script more naturalistic. Examples of this include the Chinese script, both Simplified and Traditional.
Featural
Featural scripts are similar to alphabets, however, their main difference is that they somehow show how the sound is made via the phoneme's glyph. An example of this is Hangul.
After you've chosen a type of script, you'll want to ask yourself how the people who speak your conlang would be using it. Would they have access to paper and parchment, or perhaps palm leaves and marble? Perhaps the people who speak your conlang are in the far future, writing entirely on computers? Remember, the available technology involving writing changes over time, and as such, the script will change with it. We'll get to evolving scripts with technology in a bit. This is also a good time to figure out what writing direction will be used. Perhaps it is right-to-left like Arabic is, or perhaps it's a vertical script like the Mongolian or Manchu scripts. Most scripts tend to be horizontal due to eyes seeing more horizontally than vertically, but that doesn't mean that vertical scripts simply don't exist. This is one part of a conscript that I like to pick whatever direction seems fun, although there's many different ways you can justify having a writing system go in a certain direction.
Now for actually picking shapes. You'll want to start sometime in the script's past, as this allows you to add fragments from the past to the script. This can be seen in natural scripts such as the Latin alphabet, where uppercase letters used to be the standard. The reason why this changed was due to different writing materials. Typically, harder materials, such as carving in wood or stone, tend to create sharp angles and straight lines, with little to no curves. Things such as ink on paper tend to make more rounded letters with curves and wider angles. Palm leaf manuscripts tend to avoid straight lines altogether, as it could tear what's being written on. If possible, try to obtain some of the material that would be used for writing this script, as this will give you a better idea of what restrictions are put in place by the material. Create a few symbols that fall into the restrictions the material gives them while avoiding duplicates. What I do for this is just come up with random shapes, but you could try going to an AI image generator and typing "lines" or "writing" if you're stuck on this part. While doing this, keep your script type in mind. Syllabaries and logographies tend to have more strokes per character because there are more characters, and each character needs to be unique in some way. Alphabets and abjads tend to have fewer because there are usually only around 20 characters, many of which only need one or two strokes to be unique. If it's an abugida, don't forget to make your vowel diacritics! If there is any shift in medium of writing your script, a good way of evolving your script is to try to make the same symbols with the restrictions of the other medium. Perhaps a cursive form develops for bureaucrats to complete their documents quicker?
One more thing to keep in mind: make sure your characters look like they fit together. Everything said earlier should help with that, but you may want to edit the size of characters if, for example, you find that only one or two have a descender, and the rest fit neatly with each other. You'll also want to make sure that you have alignment down, as you most likely do not want to switch with where the word is vertically with every other character (although this does sound interesting, if you have a conscript like that, please post it in the conscript forum!)
Now for testing! Try writing a few different words with your newly created script. If you like how it looks, then congratulations, you've created a conscript! If you don't like how it looks, try to edit the shapes of each letter, perhaps take some inspiration from natural scripts on æsthetic. Once you've finished with your script, feel free to reply to this post with some pictures of it, I would very much like to see your conscripts