Here are some of the ways you can reach Authors

1) Search Engines - The Search Engines are full of authors and publishers searching for different services and products. Google is the largest search engine and is one of your best sources for new customers. Microsoft Bing is also a decent choice

2) Social Media (Facebook, Twitter) - Social Media is a good way to narrow down and target exactly the customers you want. Facebook is the best option. Twitter we know very little about. If Facebook doesn't work for you, it's worth trying out Twitter

3) Author Forums and Websites - This is a really good and underrated resource. Banner Ads won't work. However, most forums and websites for authors will let you start a forum thread or page about your service

4) Author Blogs - another good and underrated resource. However, it's really difficult to get enough blogs to mention your service for it to add up. It is worth a shot

5) Print Media - Newspapers and Magazines. Advertising in newspapers and magazines only works if you have a very wide market product which applies to lots of people. Or if you promote your products and services in a magazine tailored for Authors and Publishers (a good example is Publishers Weekly)
Return on Investment varies wildly, so start with a small purchase

6) Radio - Radio is an excellent and underrated marketing tool. Many radio stations will feature local businesses at low rates

7) Television - Television is quite expensive. However, it has immense reach and there are ways to get advertising spots at lower prices
If you get a good PR or Publicity firm, they can even get you an interview on your local channel or on a national channel. More on PR firms below

8) Books - One of the criminally overlooked methods of marketing and sales is to write a book. Write a book about your area of expertise, aimed at authors. Leverage that book to become a well known subject expert
People who read your book will flock to your products and services, provided the book adds value

9) Author Conferences - There are an emerging number of Book Conferences as well as some well established ones that have been around for decades
It's an almost perfect advertising venue to reach Publishers and Authors
Make sure you advertise on a small scale first and confirm it works for you
Make sure you pick only well known Conferences to begin with

10) Affiliate Programs - A rather marvellous option. Set up an affiliate program. Let people and companies of all sizes refer customers to you. Pay them a commission - a percentage of the sale, or a fixed amount per customer
Nothing incentivizes people to help you like an affiliate commission

11) Word of Mouth - This is hugely important. Your customers are the absolute best source of new customers. Make it easy for them to tell other Authors and Publishers about you. Make it clear to them that you would really appreciate referrals. Focus on your happiest and most loyal customers first

12) Virality and Growth Hacking - This is another hugely important means to reach new customers. Quite simply, it means incentivizing your existing customers to tell new customers
Think of Virality as - Accelerated Word of Mouth
You tell your existing customers - If you like our Product, please tell your Friends. They get 10% off their first order. You get 10% off your next order
Win for you. Win for your existing customer. Win for the new customers they refer

13) Traffic Share - It's rather difficult to pull this off. You basically share traffic with other service providers and/or other sites that cater to Authors and Publishers
Quite frankly, this might not be worth the headache unless you're really desparate

14) Emerging Social Media (Snapchat, Instagram, Telegram, WhatsApp) - Facebook is very satured for advertisers now. Which also means it's very expensive. Twitter is hard to get to work. That means it's time to look at new emerging social media sites like Snapchat, Instagram, Telegram, and WhatsApp
All 4 are chat apps - so it is not as easy to market to these users, as it is to market to someone using Facebook or Twitter
Tread carefully - people are less likely to interrupt their chatting to click on an Ad
Also make a note of the whole 'bots are the next big thing' narrative Facebook was pushing to sell advertising on WhatsApp and Instagram. Bots ended up being Dead on Arrival. There is a non zero possibility that advertising on messenger and chat might never work

15) YouTube - YouTube is a very underrated resource. You make a video that covers something helpful to authors and you get dual benefits
Firstly, authors find out about you and try out your service
Secondly, Google places your video pretty high up in search results for anything related to that video

16) eLearning and Courses - Somewhat new and worth taking a look at. Just as you can write a book and establish yourself as a subject area expert, you can also create an eLearning Course
You can create a lot of credibility and trust by creating a high quality course
The course itself can become a revenue stream

17) A Public Relations Firm or Publicity Firm - Sometimes it is worth it to bring in the experts. Bring in a top notch Publicity or PR Firm and they can unlock doors you perhaps don't even know about
If hiring a PR firm then focus on having them build your brand and story
If hiring a Publicity firm then focus on them getting you mentions in well known newspapers and TV Stations. You can leverage these appearances to create trust among customers

18) We will be adding additional methods to reach authors later. We would recommend testing as many of these as you can
You never know which marketing method works best for your products and services

The most important thing is to focus on the marketing channels that work, the marketing channels where your customers are, and the ones that let you reach your customers at reasonable prices