With their noses to the grindstone, it's often tough for teams to look up and realise all their hard work hasn't moved them forward. With the tight time constraiints of an accelerator, if even a week are two are wasted in this way, that means a large enough gap in momentum that they're unlikely to have the exit velocity required to succeed in the accelerator.
The hard part is maintaining frequent, open and structured-enough contact with teams so that you can catch this.
Building in peer support mechanisms can help here (more on this below) as can a foosball table to have informal chats with your founders.
We've found that a special type of regular meeting can help too, where we simply ask them how it's going on their own terms (not the terms we'd like to impose) and ask where we can help and what's taking longer than expected. With 20 minutes once per week, we can get a sense if they're struggling in a number of specific areas - customer empathy, metrics, product, go-to-market, introductions, iteration speed - and flag up specific actions or help we can bring in to unblock them. We can also compare our notes week-on-week, using a simple paper tool we've designed called The Cohort Report.