Songwriting is the starting point of the music-making process. Songs can be written by either individual Blockstars (as long as they are a part of an active band) or by the entire band.
At the Songwriting stage, the factors determining the quality of the song are Songwriting, Musical Skills relevant to the band's genre and the amount of time of spent on writing the song.
Some Hidden Attributes also have a gameplay impact on how effective Blockstars are at Songwriting.
The hidden Concentration attribute, for example, has an impact on how long a Blockstar is able to write a song for in one sitting.
Players must decide whether to write a song using just a single Blockstar member of a band (thus allowing the other band members to engage in other activities in the meantime), or whether to tie up the entire band in the Songwriting process (which ensures that all of the band's skills are utilized).

Song Attributes

Individual songs have a variety of Song Attributes that the player must choose from, including Tempo, Loudness, Acousticness and more. Depending on whether the Blockstar writing the song has Hidden Attributes (or is in a Mood) that are a match for these Song Attributes can provide a boost to the song's quality.
The Song Attributes also interact with other Song Attributes when putting together an album - albums consisting entirely of songs with the same Song Attributes are less interesting than albums consisting of songs with a mix of Song Attributes. So if your band's Blockstars are a perfect fit for a certain type of song, that might work in the Singles Charts, but it will be a drawback when competing in the Album Charts.