Repetition is not a bad thing. You want as much footage as you can get from each shot, as the perfect video performance may have to be woven from several different angles and different takes to capture the passion that the singer can convey. Static performances can appear wooden & stilted. Movement has to be controlled but has to be there; movement via the camera, not the performer can often make for a more dynamic video.
Location, like in real estate, is everything. Why we scout out locations and are always thinking photographically; what we can shoot where. Is the location right for this artist, this song and this time of year? Is it safe? Is it allowed? If not, no matter how beautiful the spot, find another location.
Don't be afraid to get up close and dirty. At a recent shoot, there was something odd in a tree. It was the same colour as the bark, just looked odd. It was garbage, strategically placed, but garbage; a wash cloth to be precise. We ended up leaving that location with a bag full of garbage that we picked up. End of shoot meant the first stop was the washroom, for hot water & soap; although I was wearing gloves during the trash pick up, so was mostly protected. It is also helpful to have a bunch of garbage bags & wet ones along with you. Never know when you are going to need them. We tend to do this on many of our shoots, be they still or video. I never will understand why people can lug things into a gorgeous location, but refuse to pack them out again. Especially when there is a trash can just a short walk away. Leave every where slightly better than you found it is a good philosophy for camping, photography and to life in general.
Laugh. Take the work seriously, but not yourself. Have some fun. If you don't, the musician is likely to get self conscious & self critical. Nervousness isn't going to translate into a good performance or a good video. Tell people what they are doing right, and help them get there. Show them how you want them to move, where to look, what emotion you think works and be specific. Don't be afraid to be a little goofy to help them relax. It is often hard work, but a video (or photo) shoot shouldn't be unpleasant; at least not because of who you are working with.
We don't control the weather though, so laugh at that as well. Remember to bring layers. Lots of layers for those between the shots, 'hurry up & wait' times.