Break things up into milestones (preferably deliverables). Put team-agreed-upon date estimates. Provide regular updates to higher-ups on the status (maybe every

Break things up into milestones (preferably deliverables). Put team-agreed-upon date estimates. Provide regular updates to higher-ups on the status (maybe every week or two). Try green, yellow, red as classifiers on each milestone. Identify potential issues and/or blockers. Communicate those and what your team is doing to mitigate them. Document what does get achieved, and communicate that too. Come up with contingencies and compromises, such as "if we remove freature x, we could shave off 5 days, or if we have extra help testing features a, b, and c, we might be able to push up milestone y. At least, at my org, these are all considered appropriate.