If you're a big shopper or if you're a Pinterest or Instagram hound, you've probably been there — the dreaded trend trap.

You see a great outfit and you think, Oh, if I just had that pair of shoes, or a shirt like that. And then, you see another outfit. Or a sale. Or you just had to stop at your favorite store for just one thing.

This is your rapidly shrinking fashion attention span. Every day we are bombarded by ads, blogs and trend news telling us what we should want — and then making us buy things we don't actually need. There's a certain high to this kind of buying. We feel good during the initial purchase, but it doesn't last long.

That's why you need to beef up your fashion attention span. Shopping should be more about personal style, feeling good about what you wear and saving money in the process. The following steps should help you with an all-too-common problem: You have so many clothes, but nothing to wear.

Write it down

Make a list of the items you own, focusing on your favorite staple pieces. If you were to come up with three complete outfits, what does this list need? These are the items you should be shopping for.

When you're deciding what you need, make sure you have contrast in terms of pattern and/or texture. For instance, if your closet is a sea of jersey and cotton, consider contrasting with leather, bouclé, jacquard and faux or real fur. If too many colors are your problem, maybe you need some neutral pieces. If you are missing accessories, focus on scarves, hats, jewelry or bags. Knowing what will supplement your wardrobe will help you focus when you're in the store trying to make a decision.

Take a Pinterest/Instagram detox

Looking at Pinterest for outfit ideas can be good. But too much browsing is just that: too much. Being assailed by so many ideas can overwhelm and distract you. This can take focus off your own personal style, and what your individual wardrobe needs. So turn it off.

Now, stop to think about the favorite items you've owned in the past and the ones in your closet — items that are you. Why did they work? Was it the quality? Were they trendsetting or classic? Try to stick with styles that have some of those characteristics. Then check back in with Pinterest when you're more focused.

Determine your 'arousal level'

"Arousal level" might sound like a funny way to put it. But consider this: If you're shopping, and you see something you really like, your excitement level goes up. Think about that arousal level on a scale from one to 10. A 10 is something you absolutely love, plus it's marked down 50 percent for a limited time only.

But at this point in the spectrum, logic has gone out the window. This is often when your fashion attention span is at its shortest. You're focused more on the feeling than the item. And that feeling is fleeting. So take a step back. Walk away or close the browser window. Ask yourself if the item complements your wardrobe or fulfills a need you determined in step one.

Try to make purchases at a low arousal level. Without that initial excitement, you might not even like the item as much as you thought you did. Does that mean you might miss out on some deals? Yes. Is this a bad thing? No. Which have you regretted more: wasting money on something you didn't end up wearing, or skipping a potential purchase? It's probably the former.

You'll always want, want, want

Remind yourself that you are going to want something else next month or next week or tomorrow, whether or not you purchase this particular item. You just are. Is the item you want right now better than the item you will want next month? There's no way to know for sure, but if this item doesn't stack up against some of your favorite pieces of clothing, maybe it's better to pass and wait for the next "want."

Would you wear it tomorrow?

It's a simple question with a simple answer ("yes"). Beware of answers such as, "Well, I don't really know what to wear it with" or, "I'll need to buy something to go with this" or, "I'll be able to wear this in the spring when I've lost some pounds." If any of these answers pop into your head, put the item down and walk away. You just don't like it enough.

Of course there are clothes that are for a particular purpose, such as work wear or a party dress. You wouldn't wear them tomorrow necessarily, but you should still like them enough that you'd want to.

Ellen Lawson is a Minneapolis-based fashion writer, photographer and the founder of the www.theflyover.com.