Paid advertising is the only day if you do nothing now and start your actual campaign on summer.

If you start from tomorrow the best way to market your app are

1. Define the challenges and goals of your buyer personas
2. Create the buyer journey how they find the app, what are the next steps after they download, how you delight them and make them your app promoters
3. Create your inbound strategy and what kind of content would you need to help them to make their decision faster and support them in their stages of buyer journey (FAQ pages, best practices, tips, gifs, short explainer vidoes and so on)
4. Prepare your journalist outreach campaigns and your pitches. I recommend doing some A/B testing on your subject lines and email content before reaching to bigger ones

Kindly let me know if you have any questions!

Kind Regards,
Artash
http://incredo.co/