Many novice photographers spend a lot of time worrying about developing photography vision and style. While it is important, it's often overly emphasized. Style is identifying features of your work. An example would be a Picasso painting. Most everyone could pick out a Picasso out of a lineup. Since then his style has been mimicked over and over again. Picasso did not always have his modern surrealism art style. His early work was more realism. His style changed several times over his years as a painter. As photographers your style will probably change as well. So how do you develop a style? In this day and age of photography it's very hard to separate your work, but it's not impossible. The best advice I can give to develop your style is to look at work of artists you admire. Learn those techniques. Take in as much information in as possible. Whether it be certain subjects or post processing techniques. Maybe you like the composition of images from photographer "A", but you like the post processing of photographer "B". Picking out some of your favorite techniques and adding them together is how you create your style. It's like going to the grocery store picking out a bunch of ingredients and then adding them together, hopefully making a wonderful dish you can call your own. It's your own recipe. Your own style.
Vision is one of the ingredients in your style. Think of vision as seeing what others can't. This could be any number of things. Maybe you are attracted to certain colors, patterns, textures. Vision to me comes more natural. I see my landscapes in wide angle. I often shoot at the widest focal length I can. It's how I see the world. I then take my wide angle view of the world and apply my favorite techniques to meet my vision. Some see the world in a macro environment. Some see it in a telephoto world. Some see it in black and white. Your vision is your vision. It's how you see the world.
My opinion? Don't worry much about it. Learn as much as you can from as many artists as you can. From here pick and choose what techniques you like. Apply these techniques to your images. It can be before or after the shutter click. Creating a style or finding your vision takes time. Sometimes years. Don't rush or force it. Once you have your technique and vision, repeat the process over and over and your style will be formed. One day someone will look at a image and say " That's a (insert your name here) photograph."