Pictogram - syllable isn't a bad place to start.
In essence, though, writing is usually a reflection on cultural development, modified by the available technology.
You look at Sanskrit...it was written by pressing a reed into wet clay....you have a set shape for the 'impresssion' which you can shape into various patterns. The patterns were 'stylised' representations of the thing they were trying to desrcibe. Bit like writing in ASCII
They were drawing simplified pictures.
To truly 'invent' a system of writing, you first need to decide how they would have written it, and think how that might evolve into a formalised written language over the centuries.
If, for example, rather than pressing reeds into clay, the Vasudans had pressed a razor sharp claw tip through stretched mammal skin to write, you might have a language made up of hook shaped lines....
If they dribbled acidic bile onto parchment, it would be more...blobby
Take a trip back to far flung Vasudan antiquity, and think as a Vasudan
