Clothing should be lightweight, light coloured or white, and loose fitting. It should cover as much exposed skin as possible. Cotton garments are better, as synthetics generally do not breathe as well, and can be uncomfortable and cause skin rashes.
Covering your head and neck with a wide-brimmed hat, shirt collar and/or neck cloth are sensible, if not essential. Solid boots are advisable, together with thick woollen socks which absorb a lot of moisture before feeling wet.
Gaiters are useful to prevent the entry of sand into boot tops, and to protect lower legs against prickly bushes. Your feet should be washed whenever an opportunity arises, and socks can be ‘sterilised’ daily by laying them in the sun during rests and lunch stops. Dusting your feet with foot powder is also worthwhile.
It may be worth taking a fly net, as continuous use of insect repellents on long trips may cause skin irritation and could reduce the ability to sweat.