The problem isn't that you have nothing to wear because clearly you don't lack space in that closet.I'ts full of stuff! The problem is that you don't know how to shop and you keep buying the same damn thing over and over. Everyone has uniform. It's the look that you feel most comfortable in. Example of this... you love jeans and plaid shirts... okay! No problem there but if your closet is full of different variations of the same thing (in this case plaid shirts and jeans) then it's a problem. You have to ditch your typical uniform sometime and spice it up a bit when shopping. So the question is how do you actually think out the box when you've trained yourself to look only at specific things when shopping? Notice I said "trained" because that is exactly what you've done. When shopping only certain things catch your eye and you tend to gravitate towards the same exact things. How many versions of boyfriend jeans or skinny jeans do you actually need? The trick to break out of this habit is to just play around at first. Go into a store and try on different things that you normally wouldn't. It really doesn't hurt to try on clothes.
First thing you should do is to get ideas from the internet. Find looks that you like and then think about what particular pieces you like about the look. Try Pinterest for examples of different looks then go into a store and find pieces that are similar. Keyword here are pieces! Try on the look and from it you may find only 1 piece that really stands out from tons of items you've tried on. Pick the one or two that really had you thinking WOW! You're looking for those WOW pieces because those are the actual focus points that people notice first.
When I say "Wow" it could mean a few things. It may have bling (if that's what you like), it may be a bold color, a different fabric choice or it may simply be a garment that fits your body right. Don't ever underestimate a great fitting garment that fits your body right. It is even more powerful then something bold or bright. Even if people rarely acknowledge it we tend to pay attention to the fit of a garment and if it fits like it's tailored for you it adds a more powerful statement then a box cut item.
Fabric variation also makes a statement without veering too much out of your typical comfort zone. Same goes for your home decor but that's another post. Take a look at these two similar outfits and you'll notice the difference. The shaggy vest draws your eyes in and the other is ill fitting and doesn't really make a statement other than it fits the trend.
Lastly make sure you're using accessories. Accessories can really change a look drastically! When you're playing with trying on stuff make sure you try on accessories and don't over look this point. You can even start with your own closet by using what you currently have and adding different accessories to it and watch how the overall "look" changes. In addition it's cheaper to add accessories then to do a complete overhaul of your wardrobe. So play away and don't forget the WOW.