Not a book but a good resource is http://www.askalmanac.com for GTM docs (launch plans, marketing strategies, etc) that other startups have used. More on reddit.com

Couple of questions: — have you tested the idea on your ideal market? If yes (hopefully), where did you gather the data? — why specifically 18-29 y/o females? — majority of your marketing plan is actually just paid advertising. Ads work well to create awareness of the product. You’ll need creator content and organic in order to prove your concept, create trust and facilitate a need. Some simple suggestions: create lead magnets - maybe a quiz or a download where you can offer insight into the product and how it helps. Education works well in this category to show you’re a leader in the space; talk about benefits of looking after your mind, benefits of ‘journalling’, mental health, self-care etc. You can also showcase new data and science in the industry to support the need for downloading your app. Build your email list from here to directly market to them; this is much cheaper, too. influencers - since this is a product that’s linked to emotions, utilising micro-influencers and nano-influencers could work in your benefit because it’s more intimate and relates to the psyche of an individual, meaning they’ll need to trust/genuinely like the person who’s recommending it. conduct your own studies; create proof by showing a side-by-side comparison of how someone feels without your app and how they feel with it. Make sure this is authentic in delivery, otherwise it’ll fall flat and users will see right through it. If the app offers paid features; I’d set up an affiliate programme. Your app could spread quite organically over TikTok this way and content creators will earn a small % - win-win. for organic content, showcase usage of the app on a mobile, create realistic scenes of using the app and how it helps. team up with other brands or businesses where both will benefit, I.e. you could sponsor or partner with other wellness brands in-person or online. consider podcast ads; the variety of ads in a podcast is huge, sometimes totally irrelevant to the pod episode but it feels less passive than google and fb ads, as you usually end up listening to the ads as you wait for the pod episode to continue. there’s also power in showing yourself as a founder on social media! Just a few suggestions, hope it helps. More on reddit.com