This is a very easy effect,
I'm new this is my first post, I'm sorry if this is too simple of a tutorial. I'm sorry if this has already been posted
1. Start By Choosing an image
I did a Google search and found this flower and since i like flowers and they are easy to test on i choose it.
Sorry of the large size.
2. Choose the Magic wand tool
3. I usually turn the tolerance down a bit, 50% Will select too much on most images (I used 27% for the flower)