I'm actually nervous about the response being overwhelming as my app is so cool. I have a beta client, started with MVP and built it from there. Still in Beta but ready to bring in new paying clients. Wanting to rack the shotgun in a meaningful way. My clients are medical clinics. Thank you in advance!
1. Get your marketing collateral together. Your case study and testimonials from your beta trial. Make sure you have a demo app ready so you can walk into any medical clinic and show the product on the spot.
2. For this industry, perhaps consider a small digital signage campaign. If you don't know what digital signage is, it's controlled offline advertising in public places. Usually via screens or devices like iPads. They are usually prominent in places like medical centres, Universities, shops, public transport etc.
3. When it comes to online advertising. It's always worth testing both organic and paid campaigns on Twitter and Facebook. However, LinkedIn is perhaps where you will really benefit from investing your time. You should look to target the types of professionals in medical establishments who are involved in purchasing decisions for technology.
4. Yes, go offline. If you have had a good beta trial and have a working product, start lining up offline meetings to pitch your solution. Go in, speak to people, pick up the phone.
5. Consider running mobile app install PPC campaigns via Google search and the Google search network.
6. Consider app partnerships. e.g. is there an app that a lot of medical professionals already use. Can you promote your product via their app?
7. Go down the PR route. This could work really well if you're looking to start locally. Find your hook, pitch to local journalists and get exposure in local publications.
What I've written above is quite broad and there is a lot to consider tactically, but running through the points above should give you plenty of food for thought.
Before you "rack the shot gun", you need to work on this "I'm actually a little nervous about the response being overwhelming" If you don't reframe that subconsciously you won't give you marketing efforts 100% and it will hold you back.
Also, you client isn't the medical clinic, you have two clients the decision maker for the clinics who approve the purchase and the users of the app who will help convince the decision maker of the benefit. For the decision makers, I'm thinking trade journals off and online, If employees would be using the app they or the decision makers gate keeper may be on LinkedIn or other industry specific platforms.