No sales pitches.
You need great content for a mailing list to work.
Any email you send to a list of prospects should deliver something of value, not a sales pitch.
Due to this, your marketing emails should be carefully planned using useful content from your website that your list(s) will find interesting and useful.
In order to be able to do this, you need to produce new content on your site every month to then share with your list – it’s no good sending them the same stuff every time, they will simply unsubscribe.