@robertwill I have posted this quite a few times over the years on here about this...
Yes - it is possible, and for the most part it is all down to very basic business “marketing” - there is nothing different about selling music or selling a food product IF YOU ARE LOOKING FOR COMMERCIAL SUCCESS
Some people write “from the heart” and get a bit “cork sniffer” about their art. This approach can lead to success, as they stumble upon something other people dig and want to buy
The “commercial” approach is more about the traditional business marketing approach - identify a target market and develop a product to meet this need
This is how recording labels do it - the “product” is a combination of the artists (look, image, following) and “the song”
These are then tailored to “the market” - which often means writing songs to previously successful formulas etc. - which some songwriters see as “selling out” or “inferior” - but it is INCREDIBLY difficult to write “a hit”
As with business, disruptors come along out of left-field that break all the rules and are successful - which then spawns a string of copy cats - but this is quite rare
So - to sell a million in a month, IMHO you need to either...
Find the market for the songs you have already written and promote heavily to this market
Write songs specifically for a market...and promote heavily to this market
The real skill is working out how to stand out in a market when everyone is trying to do the same thing - and the answer is: “be different, but not too different”