What did you learn from your last startup?

If you want to work out what you have learned from each of your startups, you should first review in summary what you did & didn't do, so that you can extract the lessons from each of them. By the way, if you don't yet have a journal, get one.
Let's assume that for every project of yours that didn't work, it is automatically assumed that you didn't know enough. The same is equally true of all my projects. But that in itself isn't enough.

You can start to determine what you experienced, and therefore what you learned, by outlining the external factors & events around each of your startups, such as

• What stage did it get to?
• Who was involved and in what roles?
• What were their skills? their motivations?
• Who did you engage to support the project?
• What research did you undertake?
• Did you have a plan? If so, did it guide you or confine you?
• How flexible were you in deviating from the plan?

These will lead you to the important factors, like:

• Why it didn't work,
• What you still have to learn,
• What you did learn, and
• What can you do differently next time.

Next, just as I have done, list in any order you like, every 'startup' that you've worked on. For the sake of the exercise, you can include those projects 'owned' by others.
We'll come back to the learning in part 2.