Soft vs. Hard Lighting
Finding the best light for your photos is easy when you understand the type of light that different light sources produce. The Sun for example is a light source you have probably used many times before and even though the Sun is a very large light source which would usually produce soft light the fact that it is so bright and so far away makes it a source of very hard light. (Except durring sweet light hours)
One thing that makes the sun a perfect light source is a nice overcast sky because it spreads out the light like a big soft box and gives us a very large soft light source. That's why you get such soft shadows (if any at all) and even lighting across your entire image.
So if you think about light with the sun and clouds as your reference it is easy for you to look at a light source and understand what type of shadows you should expect.
A point light source will give you hard shadows which is why we call it hard light. It is typically good for a more dramatic look to your images. Hard light is good for images where you need more impact in your image, it's the type of lighting you might see in an ad for an action movie or in a horror movie. The movie The People Under The Stairs for example uses quite a bit of hard light for a much more spooky effect as did Alfred Hitchcock in Vertigo.
A broad light source will give you softer shadows which is why we call it soft light. You can also achieve a soft light by bouncing a hard light off of a larger surface like a wall or ceiling. Soft light is great for a more pleasant, dreamy or romantic feel to your images. This is the type of light you see in advertising, family portraits and romantic movies such as Eat Pray Love.
Depending on what you are going for in your final image you can decide which type of light will work best for your shot. Just remember that you can always make hard light soft by bouncing it or using a diffuser but soft light will always remain soft light.