Look around the roof and visually plan your sequence of measurements. Plan where you are going to start and finish. Don't jump all over the roof measuring here and there. Pre-label your estimate sheet, columns for Hips, Valleys, Eaves, Rakes, and Ridge Lines.
Measure everything in sequence, such as all the hips, then all the valleys, etc.Do not pad your measurements, such as 15 ft. 1 in. = 16 ft., etc. It's always better to have the most accurate measurements.The one exception to this is if you are using valley metal. When measuring the valleys, you will have to add for your laps, where the sheets lap one another and where they lap at the top
.Pay attention when reading your tape measure and writing your numbers. Numbers can get transposed. There is a lot of difference between 34 and 43. When using a 100-foot tape measure, a lot of the time you are reading the tape measure upside down. For example, a roof is 60 ft. long x 34 = 2040 sq. ft. But a roof 60 ft. x 43 = 2580 which is a big difference: 2580 minus 2040 = 540 sq. ft. or 5.4 squares.