Do build a relationship before you slide into bloggers, critics, and publicists' DMs.
Nobody likes an opportunist. Music bloggers, writers, critics, and publicists are people, not favor machines. Phrases like, “Let’s build fam!!” don’t work. Very few people get satisfaction from hungry artists clogging their DMs and notifications with links to their latest single or music video. You don’t ask a girl out the minute you meet here. There has to be some type of finesse.
Instead of trying to immediately get a blog post as soon as an influencer hits you with the follow back, try sharing their content before you try pimping your own. Better yet, when you ask for that blog post over Twitter, get all of your fans to retweet and favorite your request. Numbers don’t lie. People are a lot more willing to believe in you if someone else does first.