Here's what I would do if I was starting an artist email list. It's a big topic, but I can't think of many other topics that immediately make you money and bring people out to your shows when you get into it.
I'm drawing inspiration from -- as I said in my last conversation with an artist about this -- the initial list at Rhythm Changes in the very beginning, where I invited most of the people personally.
First, you compose a message that goes something like, "Hey, I'm planning a show where I'm introducing my new music. It would mean so much to me to have you there. I'm reaching out because I thought you'd be interested. It's going to be a very special show, but very small. The number of seats will be very limited. I'm going to give you access first, and you can sign up to hear about it here."
The immediate key to the strategy -- the thing that puts you ahead of most artists -- is breaking through the fear of being rejected by these people. They're your friends, family, and colleagues, so they'll come with varying amounts of fear depending on where you're at. But at the end of the day, reaching out to them this way will help you sleep better than if you just posted on social media and hoped they'd come, trust me.
At the top of your website, any visitor can sign up by entering their email for free. That's the second key bit: few artist websites prioritize email sign-up at the top of the homepage. Why? I don't know. It seems like an obvious winner to me.
As a start, you try to invite and get 100 of those people, ideally 200, signed-up. To help get to that number, you could start taking it to social media afterwards, but do try and get as much of that as possible from private outreach.
Then, by the announcement date for this special show you mentioned, you could fill the show within a couple days with an announcement to those 200 people. Yes, that means you have to now actually write and send them an email, but it'll be very much worth your time.
Let's say that to sell out the show, the true number of people who would need to take up your offer quickly was 40 people: 20% of the 200. Even if you have 100 people who take you up at a rate of 20% because they know you well, you could sell to 20 people or more on day one. And that's what you're going to need to do.
The rest of the marketing plan is then about how you expand beyond that: how many more seats are there, and how do you hopefully find many more people? I could take my own medicine on this for an upcoming show that I have in several months.