When you're going to record a song:
The higher the production level is, the better the review on the record
A single consists of two songs. The locomotive song (a-side) of the single is preferrably of recent date, with growing fame and popularity. You might want to support your single with a music video, to boost it's fame.
An album has 8 - 12 songs. Every song above 8 gives you a (slight) bonus on your review. Singles and albums are reviewed within 24 hours after releasing them. Better reviews affect the recordsales positively.
You have to have at least dreadful fame in one city and preferably fame in more cities to sell any copies of your record. Don't rush when you want to release records, it needs fame and good songs / recordings to sell records.
Once your single or album is finished, submit it as soon as possible to the studio, so the owner / CEO can order the discs from a factory. The supply of the discs has to be delivered before wednesday, when the recordsales are calculated. It would be nice to send the owner / CEO of the record studio a message that you've submitted a record, so actions can be taken. Also mention the desired release date.
In general records will be released on wednesday, but since the new recordsales system with pre-ordering is up and running other weekdays might be possible too. Releasing records to soon hurts the recordsales badly, you'd better wait a couple of days. Singles can be released after 30 days and albums after 112 days (2 popoyears), you'll get the “your fans are eagerly waiting” message then.
The week before christmas the recordsales will be boosted, try to plan your releases accordingly. The week after christmas shows crappy sales, try to avoid releases in that period.