most of my sales come from twitter. don't launch a game on the weekend. early in the week is good. i have a list of press people i send free copies of stuff to, and i send them at least a week before the game's release date, so they have time to write something. be really clear about basic stuff about the game in that email, like when it'll come out, how much it'll cost, and what URL they should link if they write about it (itch is cool cus you can set up your game's page / url ahead of time, then set it in preview mode to show to press). again, don't send out those emails on the weekend. i've heard tuesday is a good day, because folks tend to spend mondays catching up on stuff from the over the weekend.
i have always sucked at marketing though so no promises.