Communicate your estimates in precise ranges, do not agree on specific date. Continuously say that your estimation is a range of dates. You can show Uncle Bob’s distribution of precision as a mathematical foundation of you estimate:
Do not say that you will “try”. When you do that you give a promise to the manager which is not honest at all. “The lesson is: never try” just like Homer Simpson said:
w deep you want to go in…rom the big one and so on. You need to decide how deep you want to go into the tasks. Robert Martin recommends to go to 2nd or 3rd level deep.