@Lindon My subscriber list for my Plugins are roughly the same as yours (around 18k). Ill be as open and honest about what Ive done, results, etc since beginning my current plugin company 1 year ago.
My main focus for marketing is collecting emails. I do this in various channels (resellers, free giveaways, exclusive blog discounts, affiliates, etc).
Whenever I have a new release, my email subscribers get it first. Whenever I have a deal/bundle/sale, my email subscribers hear about it first and/or get a special/addional discount.
Any purchase recieves a thank you along with he downloads.
Some amount of time later, usually 5-7 days, i automate an email checking in on how they like the product and if they would leave a review. Leaving a review gets you a small discount/gift card to be used in the store.
As far as campaigns, it depends on what Im aiming for. A new release will get "hype" emails, 1-2/week, for a couple weeks. Then the actual launch and deal will recive 2 emails/week. The final 48 hours receive 2 emails as well for urgency purposes.
Bundles, deals and sale may get a similar treatment just less "hype".
My audience is pretty used to my email format and layout. Im usually pretty straight to the point with a bit of sarcasm. I think being yourself and not bullshitting is pretty important.
I typically can make $2000-$4000 from my email list each release/deal. These deals are usually 2 week periods.
Hopefully something in this ramble while im rocking my daughter to sleep s helpful.
