So I released No CS OK, my job board for developers without degrees last Wednesday. I got a lot of email sign ups on the first day after getting top of Hacker News and staying on the top page for 2 days. I then launched on Product Hunt at the start of this week and finished in the top 10 with over 200 upvotes.
I had a nice simple email CTA in the header of my website so that definitely helped. I also added that the unsubscribe rate was less than 1%. I always update how well a newsletter is doing as that creates herd behavior. So if people see 500 people have signed up in three days then that demonstrates value. I also didn't go for the boring "subscribe" button but a "get a job" CTA which is obviously a lot more grabby.
I also promoted the newsletter in the separate newsletter for my other website No CS Degree where I interview people Wes Bos about how they learned to code.
Naturally I used Twitter a lot as well and I've pinned landing pages for my newsletter campaigns to the top of my profile.