Shooting outside has special challenges. One of the biggest challenges is weather, especially in the early months of the year. If you are looking for a sunny day, stop. I never shoot portraits in full sun. The lighting is harsh and it makes people squint and squinting is not flattering. You want to present your people in their best light.
If it is a sunny day, I will find a good shady location with a nice background. Just make sure it's not dappled light like the kind that comes through the leaves on trees because that will cast some weird shadows on the faces. The shade of a tall building works best because the light is consistent. If you're shooting in a cloudy day, make sure the shady area is consistently shady and not partly in sun or you will have some shot brighter and some shots darker.
I prefer to shoot in full shade on an overcast day because the sky acts as a giant softbox. And you get a nice soft light like this portrait image.