[adamwi]

Many great answers already, but will add my two cents as well. All the tips regarding poker planning, breaking down work in manageable chunks, identifying the critical path to finish the sprint and so on are highly relevant but I also think there is a broader question about how work is planned and the team is managed.

The situation you describe with an ambitious product roadmap and very limited time available (and other resources lacking) is very common in early stage start-ups with very visionary founders that have limited managerial experience (I have been there myself).

In my book the team leader/manger role is to make sure the team performing at its best and can be productive, the personal productivity of the team leader is irrelevant. A common mistake is the underestimate the effects of investing time in creating an productive environment for the team.

If would be in your situation I would make a prioritised plan with time estimates (using the techniques mentioned in other posts) and then sit down with the team leader/manger/founder and refine it and agree on deadlines. This would remove pressure as the timeline is jointly agreed, then it would just be important to be very clear if any deviations come up.

If the team leader/manger/founder is someone can have an open discussion with just share your thoughts as in the post. In my team we aim for brutally transparent culture when it comes to morale and stress levels, it allows us a team to be much more productive in the long run (and we have more fun). Remember that start-ups should be a marathon and not a sprint despite working in "sprints". I hope it helps!