My recommendation is to follow one store style- and dress on clearance. Let me explain.
Find a store near you that you feel exemplifies your dressing style: like Old Navy, Gap, JC Penney, etc. These stores all have clothing buyers that dress for a specific client group.
Next, find a specific style at those stores: for me, it's knowing what type of dress pants and dress shirts are the most flattering to my body- again- most stores have their "athletic cut" or "fitted" vs loose, straight leg vs boot cut, etc.
Now that the hard work is done, all I have to do is walk in and go to the clearance rack. Lots of stores arrange their clearance by size- so I will go and check out the medium and large choices. I'll look for a color, pattern, or style that interests me- otherwise I don't consider the rest unless I'm specifically on a mission to purchase one single item (a new pair of sweatpants, a package of white athletic socks, etc.) If the shirt is from a store I have shopped from before, I will often recognize the tag and know that the garment *should* fit me without even trying it on- it's simply "this year's color" of a shirt I might already own. I like what I wear, and I feel confident and attractive in it.
I ALMOST ALWAYS try things on in the store (unless it's socks or underwear) because you can find irregularities, missing buttons, difficult zippers, etc. by trying things on. If I am at all INDIFFERENT about the item, I don't rationalize a reason to need to buy it- instead I enjoy the "savings" of NOT buying it. Bottom line is if you're not CRAZY about it in the store, you're not going to wear it any more when you get home and then it's just taking up valuable space in your closet.
When buying on clearance, if you DO find something wrong with an item, don't be afraid to ask for an extra discount because the worst that someone will say is "no." Never hurts to see if there is room to reasonably adjust - however you're more likely to get a YES if you are reasonably about what your expecting - a good rule of thumb would be the tailor fee to fix: "Can you give me an extra $2 off to match and replace this missing button?" That's $2 more in your pocket. I found a GAP leather jacket on clearance, went down to the tailor and asked how much it would cost to restitch 6" of seam that had opened on the shoulder. Then I went back to the store, and told the manager that it would cost $12 to repair- and she gave me the additional discount, because she knew what her potential cost would be to get that item out of her inventory. The jacket went directly from the GAP to the tailor, and was mine, almost brand new at 55% off a week later. Buy items off season (eg end of summer and after Christmas clearance) and put it away for next year--- but only do this with BASIC items- nothing trendy or flashy that might no longer be *in fashion* the next year. Don't buy something that's just barely large enough to wear next season- unless you have a younger brother or sister at home to take it in case you go up in size.
Last free tip for today: guys it's easier if you save up your money and buy a few pieces at the same time (like 2 pants and 3 shirts) that you KNOW you will wear together and are interchangable, instead of trying to remember what you have in your closet and matching a new sweater with a shabby pair of chinos. If you walk into a store and tell the sales clerk (male or female) that you want 3 outfits and that everything you are buying has to be on clearance- IT CAN BE DONE. You might also get a special discount out of the deal.