There are many construction estimating method that can produce accurate results, but not many that can produce accurate results in a short period of time. A time frame on minutes and not hours or work.
If you are looking for an estimating method that will both provide you will accurate results and not take up your entire day with work your best option is construction estimating software.
These programs allow you to complete estimates in a method that is quick. By using the computer to do the math equations and calculations you can save yourself a tremendous amount of work. In some cases reducing the time for an estimate to 10% of your old way.
By using one of these programs, you can also gain accuracy in a number of ways. You eliminate any math errors. These are quite common when doing estimations by hand, even if you are using a calculator. You also gain accuracy because of transposing errors, errors that occur when you move numbers from one place to another. This can be a major issue when doing this by hand, but when using a program there is never a need to this. You can write the equations to do all the moving for you.