I won't address the factors common to all digital startups here, and focus on factors that might be specific to education, and B2B in particular.

* Understanding the Sales Cycle - it's different in education, particularly K12 and HE (at least here in the U.S. market). It's important to plan revenue and projections, accordingly. The time to move through the entire sales cycle can be longer than anticipated (if you haven't had exposure to K12, for example).
* Understanding the Audience - who is it for? and who are the stakeholders? Like most B2B plays, you are likely going to interact with multiple audience types / personas - define them and be intentional with your approach towards each (whether it's via sales, customer development, implementation support, etc)
* Articulating Value - there are many ways to define value in education. Some of these are clearly financial in nature, but many, many are not. If you're building something aimed to increase levels of student achievement, teacher efficacy, etc, then think about to position your product / service in the right way.

Hope this helps and is somewhat on track.