Ideas

Use slide-in boxes to prompt shares. https://growthhackers.com/slides/the-only-metric-that-matters-by-josh-elman/

Build a community around your product to engage customers Building a community is hard work! Examples: https://hackernoon.com/building-community-for-cryptoassets-a7f5889f81b5

Create a "What to do next" email or message to onboard new users coming soon

‘Cause a problem’, then fix it to win over customers. Do that quickly and transparently. I would add a live chat widget to every site you are building + Fast…

Remind your users about your presence with regular communication Depends on your tools you are using. Read more about communication here: https://thenextweb.com/socialmedia/2014/04/29/real-growth-hacking-really-communication-hacking/

Incentivize users to share your product after they signup by offering rewards and discounts. https://www.referralcandy.com/blog/paypal-referrals/

Create "bundles" and "offer packs" for your product. No special tool for that. Depends on your product if there is a use case for you. Examples: http://www.hackerbundle.com/ghb https://apps.shopify.com/product-bundles https://woocommerce.com/products/product-bundles/

Create a sense of urgency with time-bound countdowns or deals for targeted users With the App Sumo you can build nice countdowns or provide deals for your product

Convert your product or service into a chrome extension so it opens up when your user opens up the browser. Maybe not possible for every product but a great way…

Incorporate a larger business’ product, service or API into your own to gain their user base and credibility. There are a lot of examples out there. Take a look at…