Measure the length of the wall. The guttering should tilt slightly down towards the downpipe. This is the gutter’s “Fall”. Building Code requires a fall of 1:500 for eaves guttering (please check your state's building codes). To get this fall right, install the high-end bracket at one end at the very top of the fascia. Then install the low-end bracket at the other end, dropping it 1cm from the top of the fascia for every 500cm of length the guttering travels. Once the high and low brackets are installed, run a string line between them and install the other brackets along the line. Brackets should be no more than 1200mm apart.