You know that brilliant web app that you are building right now? Yes, the one that you hope will attract millions of monthly page views and be very successful. Well try to think ahead to two or six months after you launch it. Assume that you are getting no more than a hundred uniques per month. What reason or excuse are you giving for the app’s failure? OK, now come back to present day and deal with that reason.

Of course you may think that you do not need this exercise because you are so sure that your app will be successful. You may be right but know this - so many others thought the same before you and yet experienced failure. You should check out this post from the guys over at the Vitamin blog about a web app that had to be redesigned after the initial design caused the site to fail. It just goes to show how seemingly little things can matter a great deal.
I know it is can be really hard to project into the future like I am suggesting but it is certainly worth trying. It is perhaps easier if you have experienced failure before. I was lucky enough to experience a relatively inexpensive failure that taught me to always carry out this exercise. Having little programming knowledge or money I created a small ad-supported site that users could use to notify their utility service providers when they moved house. On the face of it, this looked like a really good idea that solved a problem for users. Of course I  built it and they didn’t come - at least not in the numbers I had hoped for. Why didn’t they come?  Because I didn’t have a good user acquisition strategy. I was relying on Google Adwords, which of course was too expensive to sustain a site that wasn’t making much money.

So now, I always slap myself with a dose of reality by projecting into a failed future. It is always hard but almost always highlights a problem that I should tackle before launch or even before embarking on the venture at all.