Sometimes an image is spoilt by people or objects standing in the background but by using a simple tool in Photoshop, these objects can magically disappear.
Open your image in Photoshop and zoom into the area you're going to be working on. You can do this by selecting the magnifying tool or by pressing Ctrl + on your keyboard.
Once zoomed in, find the Clone Stamp Tool and hold down the Alt key and click on an area close to what you want to clone out. For example, on this image the grass near to the legs of the woman in the background. Once selected, let go of the Alt key and paint over what you want to be removed. Be careful how you do your strokes and make sure your follow the pattern of what ever your cloning. For example, the bark of the tree's pattern is vertical so your strokes should also be vertical.
So you don't clone-out anything you want to stay, change the size of your brush to fit. This can be done on the top tool bar or by right-clicking on the image and adjusting the slider accordingly. You can also adjust the hardness of the brush. Start by setting it at 0 and if you find it's overlapping areas you don't want to be cloned, you can increase the hardness of the brush. If you can, it's also important to sample different areas of the image so you get some variation. If you don't, the area you've cloned can look a little repetitive and sometimes obviously cloned.
Until you're used to using the clone tool it can take a while to adjust an image but persevere with it and you can get great results.
See the before and after image here: