I have a niece who is living on the other side of the world. We don't get to see each other unless we communicate via facebook.
She loves fashion and is always following new trends. I recently got e message from her that read as follows:
Wish u were here to help me sort out my Closet...... way too much clothes that I DON'T wear, or I don't know how to put the pieces together!!!!
I think this is a major issue for a lot of woman out there. 
Woman seem to follow trends and end up buying lots of clothing items without planning or even having a look at what they have and need.
My solution is the following:

• Remove all your clothes from your closet. 

• Sort everything out by different categories. ie; skirts, tops, shirts, etc.

• Do you have neutrals in each category? ie: black, white, beige/sandy colour.

• Remove those and put them aside. You should have at least one neutral in each category. If not, make a note.

• Now, look at the rest of your clothes and choose one colour item of each category that suits you the best. Think of all the compliments you get when wearing colours. That should be a good indication as to what to choose.

• Patterns that are timeless: - stripes, dots, squares, floral....are good, provided that it is not psychedelic, too bright/luminous or too large.

• Colours that will always have a comeback: -  red, navy, fuchsia, olive, ocher, pastels and burnt colours (oranges, yellows)
• You should now have a collection of items. The items that you did not select, BAG IT!
• Now take the colour items and try to match up with a neutral. Swop the items around and see what works the best.

I will add some more posts regarding this topic. You can also refer to my previous posts: My little black number and plus size woman.
I will gladly answer any questions you have regarding this topic.