I've worked in the Arizona desert for many years. Days, nights, summer and winter. Seen more than my share of rattlesnakes.
Shade is their friend during the day. They'll find a spot of shade under the scrubbiest bush, the smallest rock or a signpost and nearby activity won't run them out. We generally try to herd them with brooms to get them away from where we are working, but they often aren't willing to leave.
Never assume there isn't a snake some place. Even if you've been standing in a spot for 10 minutes, there could be one under that bush a few feet from you. Look! Park a car? You just created a bunch of shade. Start looking under it as you approach so you don't put your foot right next to a snake resting under your door.
An LED headlamp will be a must if you walk outside at night.
They aren't aggressive, but you have to develop a new approach to doing things so you don't blunder in on one without either of you realizing you are about to meet. That's when bad things happen.