My go-to list:

1. Launch your product on BetaList

2. Create a blog and write a lot. Don't create trivial content. SEO is important but write because you have interesting things to talk about, not because you have to create "content".

3. Share as much as you can on twitter/Slack/FB groups. But never be spammy.

4. Being actively engaged on Twitter (yes!) by regularily searching for your main 1-3 keywords.

5. Start soon with link building. It's hard but eventually will pay.

6. Word of mouth. Encourage and make it easy for your customers to tell others about your product (no, not by including dumb social sharing buttons!)

What not to-do:

Don't start with Ads prematurely. No matter what the platform is. The don't pay initially and will cost you a lot.