Mistake 1 - Not Getting the Information You Need Up Front
It happens all the time - you are asked to provide a "ballpark" quote on a job. The details aren't all available yet, the customer says they don't really have a budget in mind, and they'd like the job finished within ninety days. You think you've got a good idea what the project will come in at. And if you've got years of experience running identical construction projects with identical risks (but how often does that happen), you might be right. Or, as is more often the case, your "ballpark" quote could put you out of the game.
How to avoid this mistake -
Get the information you need before you estimate
Start your relationship with your customer off on the right foot. Be clear and firm that your estimate relies on a written commitment from them to provide the information that you need. If you haven't been provided with an RFQ, ask for one. Develop a checklist of the information that you require to create your estimate - design plans, drawings, etc. If you can't get an RFQ, use that checklist to ensure you have the information that you need. Until your customer gives you a start and completion date, an idea of scope and a budget - you are estimating with limited knowledge and potentially setting yourself up for disaster.
Developing a proactive approach with your customer from the start will make the entire project easier to manage. It's up to you to manage your customer's expectations. How you manage their expectations can make all the difference in running a successful construction project that leads to more work from that customer, or it can lead to running the project from hell. Put it this way - you can provide any two of these: cheap, fast and good. If your customer wants cheap and fast, it has to be clear with them the scope of the project may be affected. If they want it cheap and good - they need to understand their desired completion date might not be realistic. And if they want it fast and good, they need to know it may cost more.
Once you've got your estimate in place, get your contract done - then and only then. Make sure that your contract covers how changes to the project scope and schedule will be handled. And finally - always get it in writing and get it signed off.
The final strategy for ensuring you've got the information you need up front is to develop a reliable system to track and store your project documents. Store your estimate, contract, drawings, statements of work, change orders, purchase orders, invoices, reports and customer communication in a project document management system that provides you and your team members fast and easy access to these documents.