This week will be all about slippage: five days and five posts to understand and eliminate slippage.
Estimating is predicting how long it will take - it's not a bidding exercise to see who will come in the lowest.
You might see estimating as a way to see who will come in the cheapest. But the problem with racing to the bottom is that you might just win - and then you'll have to disapoint your team (who will either have to work harder and later, or fail to meet your commitment, or both) and your client (who will fail to pay you). You will create a reputation for being inacurate, a fibber who will say anything to get the job. Most likely, you will end up with a big employee turnaround, or mediocre employees who can't find a job elsewhere, and no client repeat business.
If you see estimating as predicting when the work will be done, things look very different. The work will take how long the work will take: the client might not like what you tell them, but they'll get over it because of the certainty, the reliability of your estimates. They can work around almost anything as long as you tell them from the start and you stick to it. Clients can work with slow deliveries but they can't work with unpredictable ones.
If you were a client, what would you prefer to hear? Which one gives you confidence? Which one fills you with dread?
1) "It will be ready tomorrow"; and then "Just one more day", and then "Just another day"; and then "Maybe in a few days, we're getting closer"; and then "I think we'll be done tomorrow".
2) "It will take a week".
And when you've gotten very good at estimating accurately, then you can start at looking how you can deliver faster.