My advice would be to focus most your efforts on finding influencers to do a review of your plugin. Spend as much time as you can making a huge list of YouTube channels, Facebook pages, Instagram accounts, etc. with all their contact details and then go through and send them all a (personalised) message asking for a review - be sure to give them a free copy!
When I started selling plugins, I made around £2000 in my first 18 months, mostly with traffic from KVR and other forums. Eventually, I had a YouTuber with around 100k subscribers make a (not very flattering) review of my latest plugin, and I made £2500 in 2 days.
A lot of influencers will only do paid reviews, typically around £1000 for a 10-15 minute video. So if you can find one to do it for free, you could then re-invest those earnings into future reviews. Getting that first one to start the ball rolling is the tricky part though…