The process I recommend to anybody who is working on a new product or feature, step by step:

• Find out what are the challenges worth solving for your target market (A)
  • What kind of research?
    • First step is: Surveys. 5 to 10 questions max (low cost for respondents) and the incentive for respondents is that they’ll get early access to the results (high benefit for them).
      • How?
        • Customer Review websites like Trustradius or G2Crowd.
        • Twitter. Find people who are talking about what you’re interested in.
      • Then ask these key questions:
        • What is your single biggest challenge when it comes to [problem]? (e.g. what it your single biggest problem when it come to creating and sharing documents?)
        • How are you willing to help us?
          • Online Interview
          • Surveys
          • Slack
        • Demographics
          • Department
          • Company Size
          • Are you a manager? (if relevant - it often is in B2B)
      • There are two ways to pay for people that work: Survey Monkey (panels); and Ask your target audience.
    • Second step is: Interviews.
      • How many? 12 to 20.
      • During interviews focus on understanding and learning from people based on stories.
      • A good question to ask is: “Do you have any stories about when something went wrong?
        • That’s how you find the pattern of pain.
          • For example: "tell us stories about how you go finding docs".
            • "Now tell us stories about when you were looking for docs and couldn’t find them".
• Find out how competitors solve those challenges (B)
  • Another way to do research is competitive analysis. For competitors or alternative solutions, you want to:
    • Analyze reviews: in this case you don’t even have to find people bc you can read the reviews online on websites like Trustradius and G2Crowd.
      • What features do people love? Look at the 5 star reviews.
      • What features do people hate? Look at the 1-3 star reviews.
    • Send NPS & PMF survey with Amazon Mechanical Turk: in this case you need to find users of your competitors or alternative solutions and send them an NPS survey. A way to do this is Amazon Mechanical Turk.
      • Example questions:
        • What is the most important reason for your score?
        • For how long have you been using [Product]?
        • How would you feel if you could no longer use [Product]?
        • Please help us understand why you selected the previous answer
        • What would you likely use as an alternative if [Product] were no longer available?
        • What is the primary benefit that you have received from [Product]?
        • Have you ever recommended anyone to this product?
        • Please explain how you described it
        • How can [Product] be improved to better meet your needs?
    • Do some user testing on competitors
      • You want to know what people love and what people hate. What people love across landing pages from different apps in your same industry will go to the top of your landing page. And what people hate, you'll address that too and explain how your solution is better.
• “Steal” from competitors (Diverge phase in Design Thinking terms): (A) + (B) = C
  • Open a blank document and write down a list of features from your competitors (A) that solve the top challenge worth solving for your target market (B)
  • Paste some screenshots that show the user flows (the steps the user goes through) for those features.
• Write down your user flow (Converge phase in Design Thinking terms) (D)
  • Use the document you have created (C) as an inspiration to write down the user flow for the feature you want to build (D)
• Put everything together in one document (E)
  • The challenge(s) you're solving for your target market
  • The feature you're building
  • The user flow
  • Add a "terminology section" Optional:
  • Add user stories
  • Add wireframes (you can use Whimsical or Balsamiq to create them)

Here's an example of how the document might look like (credits to Ryan Kulp for creating this minimal product spec document)

• You can find more examples of Product Specs here.
• Create your roadmap (F)
  • Trim the feature scope as necessary to achieve MVP in 4-6 weeks (Phase 1):
    • Phase 1 - Week 1-4 : MVP
      • What is the best you can build within 4 weeks ? Based on: What you want from a customer standpoint [Market] + What is doable [Tech]
    • Phase 2 - Week 5-8: Improvements based on what you learn during phase 1.
      • An easy way to learn is to use surveys to check if people are using your MVPs:
        • Example questions:
          • Retention: How many days have you used [Product] this week?
            • Why?
    • Here's an example of a roadmap