The old axiom of Location, Location, and Location is well placed. There should be lots of traffic, but also housetops in the area so there will be business other than rush hour.
A traffic light is ideal because it allows your customer to return to traffic.
Corners are best, but on very busy roads the corner after one passes through the intersection allows the customer to reenter traffic more easily. The near corner may be blocked by traffic at the light and many customers would be deterred from pulling off for fear they cannot get back out.
One should view all of the competition along the ‘corridor’ that your customers travel. What is the competition? Are there major brands along the corridor or are there big box discounters?
What access in and out does the site offer? Is it satisfactory, good or excellent?
Interstate sites are best, just off the ramp, but not behind the fence line with limited access. Sites farther than one mile are not as desirable.
One should obtain an option on the land for at least six months. You might wish to run a survey first, but you run the risk the land will be purchased by someone else.